HMRC Admin 10 Response

Hi
Split year treatment is claimed on a self assessment tax return, using the SA109.  
You declare your world wide income from the date of arrival in the UK, ignoring income and gains arising before that date.
Your pension is taxable in Hong Kong.
Your employment bonus is taxable in Hong Kong, as it is derived from your employment while resident in Hong Kong.  
Your pension arising in Hong Kong and paid to youm as a resident of the UK in consideration of past employment, shall be taxable only in Hong Kong.

Hi
You can declare the loss (in pounds sterling) on SA108 on the capital gains section of the online return.