Thanks everyone for your helpful input. I'm a bit windy of playing with the brakes myself especially as I'm going to Mog15 next week so I've booked the car into a local garage on Monday to have a look at it. They tell me they've looked after several Morgans before.
I'll let you know how I get on, but you'll know that all hasn't gone to plan if I turn up in Llangollen in a Peugeot!
Andy