Only ship if it makes sense financially. Shipping UK to Capetown return is around GBP 3000 IIRC. This made sense for us because we were away for about 11 weeks and the cost of renting a bike would be much higher. Maybe give Adrian at Econofreight in Paarden Eiland (sp?) just round the corner from Flying Brick a call for a quote.
RE insurance I also shipped to NZ and arranged cover locally, presume you can do the same here. RH Insurance are very helpful.
https://www.rhspecialistinsurance.co.uk/I can advise on esp. N Scotland if you're planning to come up here, otherwise try the advscotland.com forum. Note there is little or no DS riding to be had here in Scotland.

although there are trails you can do in England. It can be a little wet in June (May, September and October are often drier) so you may need waterproofs - just get an unlined nylon suit from Richa or Spada.
The North Coast 500 website will give you an idea of what to expect in the Highlands. The last few years have been very busy, and accommodation can be hard to find, but I've been living here for 26 years or so and i love riding here, weather and all.