So exactly what do I need to provide to open a bank account. .surely they'll want more than a council tax acknowledgement?
I'm not flying out to the UK till 10th September but concerned about how I'll be able to pay larger sums of money eg:- to property agent's, fees, deposit plus 6 months rent?
I'm not sure our US cheques are valid in the UK. Any advice would be most appreciated
It depends on the bank. However, if you have a council tax statement, that should be ok as proof of address. Utility bills are also good at most places. Beyond that, it might be tricky. If you know which bank you will use, you might check their website or call them to see what they will accept as proof of address.
You'll also need your ID (passport) and your SSN (for your taxpayer ID when they ask if you're liable for withholding from any non-UK countries - not the actual card, just know your SSN!)
US checks
can be deposited at UK banks, but they take about 6 weeks to clear. You're also at the mercy of their provided exchange rate. If you want to pay for something with a US check, the merchant probably won't accept it. Checks are not very common here. Most merchants will want a bank transfer, so you'll want your UK bank account set up ASAP. You could do a bank transfer from a US bank account but the fees are probably pretty large. (My bank back home wanted $60 per international wire transfer!) Many will take credit card payments (you can use your US card) but may charge extra for it.