Hi Phatbeetle
have a talk to your bank and pop in to see them and talk to the bank manager - banks can often match or better other deals when it comes to loans. I took a loan out for this purpose back in 99, I could vary the terms so that I could pay off within a '18 month plan' rather than other places who could only match it if I borrowed more or something.
I know with recent immigration status it might not work, but no harm in trying!
Else, look online for the comparison websites and have a look through for the best amounts to borrow compared to interest rates and payback term/time.
Alternatively - another course of action is a bit more hands on, but could help your overall cashflow - take a look at some 'bargain cars' on Autotrader.co.uk and say pickup a 7-10 year old Vauxhall Astra or Ford Focus for around £1000-1500. Find a nice one, get it inspected say around £150 (this will help ensuring you dont buy a moneypit in repairs of a vehicle) and that'll leave you around £3-4000 in your pocket - I say that by the £200/month saving you'll have available over the period of a loan payback term had you got one. Any repairs and upkeep can be budgetted from that.
Another positive for if you do get a loan is that it'll help with building your UK credit rating - so long of course you don't default!
Lastly, nip to WHSmith, and get a copy of What Car or Which Car etc type publications, they have sections which talk of all the different financing options etc - pro's and con's - however they do tend to be for new cars, so your £200/month budget may allow you to get a 'new' car with the clause that during the term, you'll never 'actually' own it.
Just putting more options for you up there, help you make an informed choice !
hope it helps - Cheers, DtM! West London & Slough UK!