So I've bitten the bullet and odered a replacement B-Max.
Spare wheel (pretend type)
Against my better judgement I've accepted the 15" alloys in order to get Air-Con, which the Studio won't allow any more.
Only concession from the Dealer was the spare at No cost; and we used the traditional £2.5K loan for a month to get the discount from that.
If it performs OK, without problems then it will be fine for an old so-and-so like me.
I may be back to get advice on all the fancy bits to turn off!