Welcome Angela and thanks for joining.
Sorry to hear of your plight.
The important piece of missing information is - how severe is this leak, and what inconvenience is it actually causing you, that makes it difficult to live with?
If it’s the rear crankshaft seal then it’s either gearbox (automatic?) out, or engine out to fix this.
Is the leak bad enough to result in an MOT failure, or has it been previously listed as an Advisory?
If you can live with it between MOTs, then you could consider getting the offending area cleaned just prior to MOT and hope you get away with it - which you may well do, unless it’s a drip.
There are so called ‘Stop Leak’ products on the market, which you add to the engine oil. Personally, I don’t favour them since they effectively ‘attack’ the rubber of the seal, and will affect other engine seals. I suppose it all boils down to:-
Severity of leak? When MOT due? How long do you intend to keep it?
I think you already appreciate that fixing it would be an uneconomical process with a car of this age, unless it is a low mileage/ superb in all other respects - example.
Perhaps you could colour in the detail and let us have your thoughts Angela.
Kind regards,
Gareth.