When I was preparing to move to the UK in July (didn't actually move until September, but was trying to make preparations), I opened an HSBC account in the US as well, hoping to pave the way for the account in the UK. At that time, they were also charging the $200 to open the UK account from the US. However, I was able to open an account at a local branch the day after I got here. Although it was a good thing I had a US account, because without an HSBC US account, they wuoldn't have allowed me to open a regular checking and savings account at the HSBC here.
I did have the advantage of having already gotten a flat, so I could show them a signed rental agreement as proof of address. By the way, the local estate agent was happy to work with me remotely. I paid the normal security deposit and first month's rent via wire transfer from the US. I didn't have to provide any credit history in the UK, nor did I have to pay several months in advance. I did have to provide a reference from my landlord in the US, proof of employment, and I believe they did a credit check on me in the US. With all of that, they were happy to rent to me without any 'extra' up front deposits.
So, first, if you can find a good local estate agent who is willing to work with you, you might be able to find a place to live before you come over (that was a HUGE load off my mind). And, if you open an HSBC account in the US, HSBC in the UK is happy to provide you with a 'comparable' account in the UK upon arrival without any fee.
The only risk I ran was that I rented the flat unseen (except in a few pictures). However, it was a furnished apartment on a one-year lease with a 6-month 'opt out' clause. So, I figured if the place was terrible, I could bear living there for six months while I lookded for a better place.