I'm of the opinion that it just doesn't matter. A bank is a bank is a bank.
Yes!!
I've have accounts with RBS, Halifax, Santander and Nationwide for different applications. I'm not afraid to shop and switch banks around for what I need/want. They all have pro's and cons and yet, they're still all banks...
Currently liking Santander's current account interest rates, but getting annoyed with the fact that the fee is more than last year, so may switch soon. I like RBS's online banking app and hate Santander's app. Halifax is always such a huge wait with their customer services, and Santander feels really clinical. RBS has nice customer service, but they're always trying to sell me something. Nationwide won't let me do online banking for the type of account I have! (but good interest rates!).
So basically, go with something that will actually let you have an account as a person new to the country (this is how I ended up with RBS in the first place, as my company vouched for me), and then keep an eye on it and move around as and when you can. Banks now have switching services that make it so easy!