I have twice taken LHD cars back to the UK and ran them for a total of 6 years. Never had to change the speedo on either car, I did have to fit repeater indicators onto my Mk 2 Golf in order to make it UK spec. Insurance was no more expensive than a right hooker and it even provides you with better security because the twockers find it confusing when they break into your car only to find the steering wheel is on the wrong side!
You can get most of the mods you will require from a reputable scrapy prior to your MOT (dont get a speedo from Appolo 13). Many years ago it would cost you an arm and leg for the insurance but it makes very little difference now as we are in the EU. It can be a bit of a bugger overtaking white van man though and is a great test of manhood on blind corners.
Depends on a few things but its no different to a right hooker if over ten years old, if under be aware even with a cert of conformity you may now need to get tested for already mentioned stuff ie lights and speedo (not mot not sure of test name for cars, bikes its mvsa).Also reverse of bfg if only single fog/rev lights fitted, none of above is a drama so no real concerns
RUBBISH! There is no requirement that the speedo is calibrated in miles HOWEVER if your speedo shows kilogrammes or whatever, ensure that this is shown on any MOT cert you get for the car. My car is LH drive and has a killogrammes speedo but the twonker at the MOT station has shown the figure in miles on the latest MOT cert.