Yeah the obstacles with getting work permits and all that stuff flattened out can be a major pain in the ass if you have no EU citizenship or easy ability to get work abroad.

I don't know about UK specifically but I know a lot of European countries have rules in place where despite merits, qualifications etc of a foreign candidate they'd much rather give priority to an out of work citizen before a foreigner.

I've encountered this when I was trying to get work in Canada despite having a pretty stellar work record, qualifications and abilities.

Personally, London isn't exactly my kinda place I'd want to be in without a job so I'd say if your finances are at risk of taking a hit in the midst of searching for work, I'd probably leave. I mean possibly there's a place out there willing to get everything green lit and ready to go with no hassles, but I feel like it'd be a bit tricky to find. London's hella expensive and not somewhere I'd be wanting to be waiting on a dream.

I'd also advise against trying to get in too deep working an under the table sort of job as means of staying afloat and doing anything that'd violate a visa's intended purpose or length of stay. I've known a few people who tried to do that due to being in somewhat similar situations and have been deported. Very few people slip through the cracks and have things magically work out for them and be alright with that route.

As far as travel goes, if you desperately need fresh air time to clear your head from being overworked(or other issues) and have the funds it might be worth a go. I mean we all need breaks especially in long bouts of working. As far as the length goes, I mean honestly that's up to you, as you said a year's time might put you back a bit in a fast paced industry. Obviously avoiding any shots to the foot would be a good thing.