[JAS84]

The set in the Liverpool Arena looks amazing.

It was incorrect to say that it's the "first time another nation has hosted for the winner" - as the UK have done it four times before on behalf of someone else.

I thought that. But I think on those past occasions it was just a case of the winner not hosting the following year, rather than the UK doing it on the winners behalf which is what it’s been sold as this time. This time Ukraine is literally at the heart of the contest.

This is definitely not the first time the UK has hosted for the winner, and on one occasion another country even did that.
en.wikipedia.org 

1960 - NTS in Netherlands declined to host for financial reasons having hosted the 1958 contest. UK was 2nd place in 1959 so was invited to host instead.
1963 - RTF in France declined to host for financial reasons having hosted the 1959 and 1961 contests. 2nd and 3rd placed countries Monaco and Luxembourg also declined, so they invited the BBC to take over.
1972 - Tele Monte Carlo in Monaco couldn't find a suitable venue, so the UK hosted on their behalf.
1974 - Luxembourg won twice in a row, and RTL couldn't afford to host again, so once again the BBC were invited to host instead.
1980 - IBA in Israel declined to host, having done so the previous year. Spain's RTVE and the BBC both declined, so it ended up being hosted by NOS of the Netherlands.