You will be subject to CGT on the capital gain.
You should be fully exempt from CGT on the capital gain arising.
You may be exempt from CGT in the tax year of your disposal, however if you return within 5 tax years the gain would then be charged to UK CGT.
You should be free of CGT providing you sell during a complete year of non residence (as the 5 year anti avoidance rule should not apply to you).
Using a company in a treaty country such as Cyprus, HK or Singapore could be attractive in reducing withholding taxes.
A Switzerland, Cyprus, Denmark or Spanish holding company would be a good option
A Singapore or Hong Kong company would be useful.
A BVI, Seychelles or Belize company would be a good option.