This might be a stupid question, but I've properly confused myself...

If I'm flying back from Croatia to Heathrow and then travelling on to Wales (home) a few days later, do I need to book via

https://quarantinehotel.ctmportal.co...tine/Home.aspx

...(and pay £88 each) for our day 2 tests, or can we use any private provider and save some cash? I wouldn't be worried but I'm paying for four people so I'd definitely like to save if I can! I can't quite seem to work out which rules will apply to us.