From memory, I'm fairly certain you'll need to send ORIGINALS ... of your Bank Statements [along with copies] at least ... Steve. I realise this is a bit of a hassle ... considering you're in the UK ... but best to be on the safe side! As regards your annual Mortgage Statement, I imagine it would be the same story.
Thing is, it so happened I was still in the Phils when MY wife and I lodged OUR papers ... which made the process a whole lot easier. Plus, my mortgage had been repaid a couple of years earlier, and it was the 'Title Deeds' that were required. In the event, it might be worthwhile awaiting others' responses here, as THEIR opinions could well differ from MINE!