Assuming you own your home in New Zealand and you are keeping it, you will have to pay the 3% surcharge on the standard residential property stamp duty rates. See paragraphs 2.1 and 2.12 here.
The first £125,000 will be charged at 3%, the next £125,000 will be charged at 5% and the balance of £190,000 will be charged at 8%. Your liability will be £25,200.
I hope this helps but let me know if you have any further questions.
It depends on the terms of the family trust. Take a look at section 2.21 here.