Unless the car needs some specialist 'Morgan Specific' work I'd probably stay clear of main dealers. I'd try and find a local classic car club and see who they recommend - brakes, engine, rear suspension is all fairly standard, and interior trim can be refurbished/updated for a fraction of the Morgan main dealer prices at a good independent car trimmers. Front suspension is a little more tricky but sounds like you've already had that done, so hopefully all it needs is a good dose of fresh grease. The joy of a 1979 is it's tax and MOT exempt.
If it was mine, I'd go through the engine - full service, replace fluids etc, then do a thorough brake check/overhaul/fluid change, smack a load of grease in the various nipples and then take her out for a spin to see what issues there were. If you're lucky, you could be back on the road for £100........
