Converting a U.S. RV for use in the UKFolks buying RVs in the USA and shipping them home to the UK are faced with issues such as the difference in ac mains voltage and frequency, and differing TV systems. Here's what forum member Paul Chatwin (aka UK-RV) did when he returned to the UK with his class A motorhome.
I installed a 230V to 110V transformer, purchased from Airlink Transformers. We got the 5600 model.
We decided to leave everything in the RV at 110V; That's what the RV was built with and I see no reason to change things. Electric kettles and other small appliances are just as cheap to buy and ship from the US, and there are even suppliers of 110V stuff in the UK.
Even if you add 230V outlets you'd still have the main 110V appliances (microwave, washer, air conditioner, etc) to deal with.
Our coach has an Energy Management System (EMS) which controls all the electrics. I'm not sure it would work properly if you had two feeds coming into the RV (one for 110V items and the other for your 230V outlets).
Why complicate things when all you need do is use the transformer to bring the voltage down to 110V; It's nice and easy to calculate what will work too as (roughly) you get just over double the amps off a UK supply (UK 16amp will give you a supply of just over 32amps in the RV at 110V).
There is the issue of mains frequency (50 Hz vs 60 Hz), but nobody has found a way to solve it that I'm aware of. All that happens is your clocks run funny (you set your microwave to cook but use your watch for the timings). Some people have had a few issues with the washer/dryer (control board), but nothing that resetting the dial control doesn't solve. It's certainly easier and cheaper than buying/fitting 230V microwaves and other appliances.
Regarding the TVs - take a look at 110220volts.com where you will find dual voltage and multi-frequency TVs and other electronics. This is a good way to solve the TV problem (though I've been told you can use a Freeview box thru the AV socket and UK TV will work on a NTSC TV set, but I haven't tried this).