It's all Time, Time, Time and Contacts. Do whatever helps you build time at the fastest rate. It will probably be the best paying option as well. I never went the instructing route but it is great for making contacts and those contacts will possibly be useful.
I started in the bush. Great for building time but lousy for making contacts. If I'd been married at the time I doubt it would have lasted.
The U.K. licence is expensive and a lot of hard work but it was the best investment I ever made. Having a Canadian ATR didn't mean a thing. I had over 7000 hours, most of it command, half of it turbo-prop command. I had to do the licence from scratch with the exception of the Signals exam. (The ME time was all flown in a country far far away.) The time did matter when it came to getting a job.
The U.K. is a happening place for aviation. So many people, so many places to go and so many natural and man made barriers.