Flying to DUB then travel onwards to UK
 

Since the country I am in is still on the red list in the UK but not in Ireland, I am planning to fly to Dublin. I would then plan to stay 10 days in Dublin in a hotel before either catching the Holyhead ferry or getting the train to Belfast and flying over to Bristol.
I have been double vaccinated with AstraZeneca although whether the UK or Ireland recognizes the vaccine certificate I have, I don't know.
I was wondering if anyone knows how closely they check documents in Dublin on arrival (eg proof of hotel reservation, onward ticket etc.), and if I had to go over to the UK before the full 10 days was up for unavoidable reasons, such as family illness, could I just go, or would I have to do a 10-day hotel quarantine in Holyhead? Or could I even be stopped from buying a ticket by the ferry company?

Are you basically asking if you’ll get caught if you don’t comply with the requirements? Probably worth pointing out at this point that discussing how to evade legal requirements is against Flyertalk terms of service.

Staying in Dublin for 10 days before entering the UK does not break any requirements that I'm aware of (although it is difficult to keep up with all the changes). Thanks for your response.
If anyone has experience of flying in to Dublin from a UK red list country recently, please share.

I don’t know about entry to Dublin, but if it isn’t a red list country you are coming from then you would only need to isolate at a place of your choosing, no one will be interested in your subsequent travel arrangements at your time of arrival.

from Dublin to the UK, you need to complete a plf if you have been outside the CTA within the last 10 days. If you’ve been in a red country then only certain airports are allowed as entry points and you need to go straight to the quarantine hotel for 10 days. There is no exception for family illnesses.

Make sure you count the days correctly.

For the UK your day of arrival is exceluded from the count.

So arrive on a Monday that is Day 0 and Tuesday starts the 10 day count.

I see, so Holyhead isn't an option by the sound of it. I think I'm just going to wait a few months, until we're off the UK red list!

It may be a while. They are faster putting countries on the red list than taking them off, unless there are votes in the removal from the red list, in which case it happens prematurely.

I can see that 11 days in Ireland is probably a cheaper and far more attractive alternative to confinement over the same period in a quarantine hotel near Heathrow. Until this week's announcements I'd been considering a ten-day tour of Romania for similar relief.

Dublin has it's own restrictions to enforce, and has little interest in the UK's red list. On the other hand the UK authorities have some awareness of the potential abuse of CTA internal border regulations and procedures: and an exit stamp from Jakarta (or wherever) could be an embarrassment to anyone seeking to circumvent those regulations.

It is unfortunate that you can spend 9.5 days somewhere like Dublin and still be suck with the full 10 days hotel prison here. But that is the way the rules are. I believe the authorities are quite adept at detecting people that try to dodge the 10 days by transiting places such as DUB. There are however plenty of places you can do a 10+ day stopover in to avoid the hotels. Dublin is attractive of course as you would not then need to isolate when coming into England. If you are recognisably vaccinated then isolation is not a concern.

You seem to be saying that your intention was, after all, to use Ireland as a back door into the UK and not to spend 10 days in a hotel there.

I have been looking through dozens of options, routes, covid regulations in multiple countries, just trying to even understand what is going on. For example how can Ireland and the UK sign up to a common travel area and then have completely different rules on who can enter that area? The whole thing doesn't make sense to me at the moment, so I think I will just stay put in Indonesia rather than face such a stressful journey.
Maybe Indonesia will offer Boris a huge trade deal and we will get off the red list.

The Common Travel Area provisions only apply to UK and RoI citizens

The UK decides who can enter the UK and Ireland decides who can enter Ireland. Being admitted to the UK does not mean you would be admitted to Ireland, and vice versa, even if there are ways to cross the UK-Ireland border without coming into contact with authorities.

Every Schengen country has different rules on who may enter, yet one could enter Schengen country A and then travel to Schengen country B perfectly legally even though one might not be permitted to enter Schengen country B directly from outside Schengen.

My experience with the Schengen visa (for my wife) was that we had to apply for a specific country, but once we had it we could enter any Schengen country (and in any order). For example I remember one year the visa was from the Czech Embassy but we entered Schengen in Geneva and there was no problem. However the CTA doesn't seem to be like that, which means I guess there must be passport checks between Ireland and the UK, or some other way of checking (plainclothes immigration officers roaming around?).
So in conclusion, I'd like to get back to the UK to visit my parents, but not to the extent of smuggling myself in - they'll have to wait for the prodigal son (joke). Anyway the compulsory 8 day quarantine in Jakarta on the way back (you get a wristband that beeps if you even try and leave your hotel room!) is enough to put me off travelling at the moment since I get claustrophobic. Perhaps in 2 months I'll look at it again if some of the restrictions are lifted.

I was talking about covid restrictions in Schengen not the precovid situation.

With a visa from CZ, CZ should have been your main destination in Schengen. You were entitled to seek entry in Geneva, but they could have refused entry if they decided to question you and discovered you had lied on your application. In practice most people don't lie, most people aren't questioned extensively and a few people do get through when they shouldn't.

It's the same in the CTA. There are no routine checks on the UK/Ireland border except when flying into Dublin airport from anywhere, but there are occasional spot checks (usually, they wear uniforms), and the added complication of the immigration rules (and now the covid rules) not being identical. A very small number of people will therefore, deliberately or unwittingly, break the law when crossing the border. The fact that they don't get caught at the time, or don't ever get caught, does not make their actions legal.