For the muslim law of inheritance is same whether he lives in UK or Ksa. Yes there maybe some difference of opinion among scholar. This law of inheritance is not from ksa but from islam.
Accepting it not will cause enmity ? How can you explain.
Wearing burqa makes some people uncomfortable? So Muslims should stop it ?
Op already said he is adopted , reverted and mother died. So option of getting it as gift is not available. In both the cases he is not entitled to inheritance except 1/3rd of it If will was made by parents. But he needs to confirm it with some scholar .