I appreciate everybody's input.

So, assuming I took the FR flight 24th morning. €16.99 fare, €35 luggage (necessary), €120+ taxi and for return MAN-EIN on the day needed = Ł19.00 + Ł35 luggage (necessary) + €17 train to town. Total around Ł250ish.

BA: €24 in return train fares to the airport, possibly negated by finding a ride to Brussels (very common from Maastricht) and then hopping on the train. €150 return airfare with luggage.

I didn't look at DUS because it's expensive to get to, and the fare wasn't great. Furthermore, FlyMaybe. I've been burned like that before.

I did do my research before I booked, and I booked a bad flight because it's the best of a bad lot.

I was really just concerned with the ability to bail out of LHR and hop on a train if IRROPS looks like I'll be trying a chicken sandwich over an air conditioning vent to try and recreate that turkey feel.

I'm afraid I'm over a barrel. I figure if I try and go I stand a 50/50 chance of getting home. If I don't try and go home I stand a 100% chance of not getting home.

If not... do they do a turkey sandwich in the lounge and does any fancy guesting me in??

I've taken domestic flights on Christmas Eve afternoon quite a few times. Of course disaster is a possibility, but in reality it's actually a small possibility.

In my experience, by the afternoon LHR is much quieter, and the staff are rushing to get the last flights out as quickly as possible because they want to go home too.

Fingers crossed you'll be fine, and pouring grandma's gin well before the midnight carol service ;-)

Sing along in your heads.
5 cold gins
4 final calls
3 lost bags
2 magic beeps
And a bomb scare in terminal three.

Would you be too late for the last direct flight BRU-MAN at 21:10 on the 23rd?

Failing that, surely a direct Easyjet/FlyBE/KLM/Jet2 flight AMS-MAN would be much less hassle than changing at LHR - even if it's more expensive.

Sadly I've had to completely rule out travel on the 23rd. Exams finish way too late to get from the exam building to the station to the airport, even if I have my bags with me in the exam.

AMS is more expensive than going through BRU, and the Dutch railways are as notorious as LHR for shutting down in the bad weather. Zaventum, even if the railways are on go slow because of the weather, is much closer and therefore cheaper in a taxi in event of IRROPS. And sleasyjet charge the same for baggage. Plus, the train to and from AMS can add anywhere between €24 and €50.

It was Christmas Eve 2013 when LGW went into meltdown wasn't it? Flooding killed a key generator or something. I had an evening flight to EDI that was cancelled in the morning. I was extremely proactive, booking myself on an earlier flight from LCY immediately, and then dealt with the cancellation and money part later. Everything worked out fine. I've travelled every Christmas Eve since and never encountered a problem. Went from LHR last year, in order to more enjoy the festive spirit.

You have chosen savings over comfort/de-risking, which I can totally understand.

In addition to the best advice above (asking the airline to 'protect the return' which in my limited experience they will do) I would add that if irrops happen, then is the time to throw cash at it and sort it out later. That's what your credit card is for. As long as you have been reasonable - for example, renting the cheapest car at their partner Avis in LHR rather than the X5 you are used to - you will rarely be questioned on asking for reimbursement.

I think you are overstating the unreliability of Eurostar. Personally I'd be far more comfortable booking the Eurostar to London than a flght from Brussels (or Paris) on Christmas Eve.

I'd think the West Coast is the more unreliable aspect of the train route to MAN, but I'd still opt for that rather than an indirect flight via LHR.

The direct flight clearly beats both though.

I cannot take the direct flight, discussed that at length. Stuck with a connection.

Not booking the Eurostar. Way too many things to go wrong. 5 trains + walking between St Pancakes and Euston means too much space for error.

My question really centered around what happens if it all goes wrong on the day. The answer is: contact BA and then find your own alternative and sort out the whys and the wherefores later on.

Damn, I was hoping to use the BA dime to rent an X5 - the only chance I'm ever going to get at driving one!

I think you are overestimating the chance of things going wrong.

By all means have a contingency plan, which you already have.

If BA and Eurostar had a 50% chance of their services not operating (barring unforeseen events - I'm sure they foresee everything you say) then they probably wouldn't run any at all.

I'd be ten times more worried about the exam than the trip home.

My last exam is Advanced Econometrics, HIDDY. I'm already anxiety drinking about it.