So, sorry, which country in the UK are you renting in? From what we did here in Scotland -
Looked at places on Rightmove. Looked at the area, public transporation (important for us) routes, etc. Contacted landlords in advance to set up viewings. Arrived, checked into hotel, slept for two days, then went looking.
In advance, liking one of the flats, got pre-clearance of my credit, etc., to rent from them - filled out their application forms before we left the States. Turned out that was the second (or third?) place we viewed, and were ready to sign the lease as soon as we saw it. (It was vacant.) They were aware we were new in-country and didn't have a UK bank, and took the first month's rent and security deposit using a credit card. We saw the property on a Wednesday afternoon and signed the paperwork Thursday at about 11:00am. Then went to Ikea and spent a buncha cash on basic furniture that was delivered that Saturday morning. We moved in on that Sunday. (Had been at a hotel up the road.) Groceries were delivered by Tesco that evening.
The power was on when we arrived. We contacted the national grid to find out who the current supplier was, and ended up staying with them. Handled everything over the internet and telephone, retro after we got into the flat. No security deposit required. Once we had something in writing from the energy company I was able to go open a UK bank account, and then set up direct debit for my rent. (Most landlords want direct debit, I believe.)
The cable/internet took several weeks to get installed. Fortunately, when we needed to use the internet almost all the coffee shops/restaurants nearby had it free, as does the local library. Downtown Glasgow, I think, has free wireless just generally "around" down there.
Good luck!