Last one to get 17a Something very useful from East Coast city out of centre (4) looks like Boon but can't find an east coast city containing those letters.
Plus Clue of the Week Home - and not home somehow (2,1,3) In a ???
Thanks both, I see it now. Bit naughty in the clue, Boston is a town not a city despite having the biggest parish church in England, it's not a cathedral!