My two penneth - In my view firmly drive it till it breaks, essential basic maintenance and quick DIY jobs, if the clutch gives out meh! Could go tomorrow, could go many thousands of miles.
If it gives out:-
A - You are never going to be without transport.
B - There is always something around here which will fill the gap and is probably as much of a known quantity as the C5, maybe the Vel Shatis, a Picasso, always an Ovlov or two knocking about, who knows..
C - Miss HN very much seems to be an enabler so no need to worry about the "Told you not to buy rubbish old cars, why can't we have a nice Aldi like them at no 22.."
D - If you fix it you'll probably swap it for something else in the next 6 months anyway and lose your investment.
TL:DR - drive it till it breaks, plenty of decent choices always about for replacement when the inevitable happens..