Sorry to hear about your loss. I went through the same exercise several years ago, and there's nothing to worry about.
No tax implications in the UK, and of course none in the US once the estate is settled. In my case, the amount was not large, but not insignificant (certainly more than $25,000). The money from the estate proceeds was in a US account and I simply wrote a US check on the account, deposited it into my UK bank (in $US). After about 6 weeks, the funds (in £'s) was deposited into the UK account.
I was lucky, over the 6 weeks, with varying exchange rates, the rate I received on the day of transfer was pretty much the rate on the day I deposited the funds. Blind luck. Transferwise has a pretty good reputation from what I've seen with the funds arriving much faster.
Once in your UK account, then interest must be declared to both the US and UK, blah, blah. The same for the time it was in the US, the interest if any must be reported to both the US and UK if the funds were yours for a period after the estate was closed.