It's pretty straight forward
I've imported half a dozen vehicles into the UK, and it's actually very straight forward.
MikeS has stated the procedure. But no MSVA test needed if the bike model has already been through EU type approval (the case for any bike model already sold in the UK, ie. a parallel import rather than a grey import).
I have used Aladdin Freight (in Oakland, CA) many times, and found them to be absolutely superb. $450 all in, for a bike to the UK. Takes about 4-5 weeks. No preparation needed, don't even need to drain fuel or disconnect battery. No crating either, it just sits in a container.
If you want any info at all, please email or PM me. Obviously the financial/tax side of this procedure is somewhat flexible, and this is definitely worth talking about.
More than happy to help, so don't hesitate to ask.