Here's my two-penn'orth GDL, for what it's worth:
You may be 'falling between two stools'. You don't say what modifications you have made to the car. If it is pretty standard under the skin it will not interest the Hot-rodders and the external appearance will put-off the standard Minor fans.
If you have carried out extensive 'improvements' to the engine, transmission, brakes and suspension then are you advertising it in the right place? There are specialist Hot-rod magazines and websites which would be best.
If it is pretty standard underneath then I can only echo the advice to lose the wheels and number plates, but even then the matt black finish will not be to everyone's taste.
Good luck selling it though, patience may well be rewarded, even after what I've just said the right person may not have seen it yet.
