I concur it's from the '89 (and maybe '90) range of Foxes.
Hard to pinpoint exactly which model, perhaps that could happen with some knowledge of the serial number of this and other suspected models.
I see it has had a few riv-nuts added to the wishbone, and some to the seatpost!
Evidence they exist potentially?
https://www.retrobike.co.uk/threads/campagnolo-hubs-on-mavic-261cd-wheels-with-campagnolo-cassette.493907/#post-3737759
I’m sure I regularly deal with Retrobike members via eBay, some more easily recognisable than others via their usernames, but the ability to communicate with them isn’t as easy as on here.
Would it be worthwhile having a list / thread on here where RB’ers share their eBay handle in order to do...
Are you sure Campag didn't make a 7spd MTB freewheel? Perhaps not Centaur/Euclid - but I'm sure there was an Olympus 7spd freewheel.
The 8spd set-up on my Kona Explosif didn't work too well until I had an all Campag arrangement of cassette, chain and jockey wheels, but now operates smoothly.