Hi,
There's numerous insurance related threads on this section of the forum ! have a little search through !
I always mention (in the threads I do/have responded in) that the cost of insurance will vary according the the kind of car you want/buy. Automatic transmission cars are very commonplace so you'll have zero problems there as every segment of car models will have that option/choice.
Other significant factors to the cost of insurance will be if you have a full UK licence or not, the amount of UK driving experience you have, if you are on the electoral roll or not. Then after those, the usual aspects of your address/postcode for where you live and the car is kept, make/model/value etc.
Over the last few months, the insurance industry has been raising premiums due to economic factors, the cost of claims and payouts rising generally etc and it's likely to continue in an upward trend for the near/mid term future.
There are all the usual car insurance online specialists and aggregrators, so do check those. I'd suggest combining that search with specialist insurers and brokers who will have special schemes in place for those new to the UK etc. All of this is tedious and can be time consuming so I also suggest calling up some of the specialist insurers and talk to them about your scenario before they go through all the 5-10 minutues of gathering your details for a quote. Insurance companies will search your Credit History Report when providing a quotation and if you have too many searches, it negatively impacts your score = I think it's relatively minimal though as the credit reference agencies know many people ring around when it's policy renewal time etc.
As for buying a car, that's the easy bit really! lots of choice, new or used and plenty of good garages and bad ones out there. It really does pay to do your homework properly when buying a used car in this regard.
Cheers! DtM! West London & Slough UK!