Sounded easy, except I had no idea what I was looking for. A further PM to AB clarified the situation somewhat and on removing the glovebox/underside trim I was confronted with this:Spongy brakes are often cured by adjusting the link rod between the master cylinder and pedal box. Unhook the glovebox straps so it drops right down, remove the under column trim panel and locate the cross bar. Slacken the 17mm nuts at each end, and turn the rod until the brake pedal starts to rise. Three full turns often dramatically improves pedal feel. If the master cylinder was faulty, you'd have brakes that go to the floor and which need 'pumping up', as well as fluid loss.
The link rod is a thin metal pole which as described above, runs from the pedal box to the master cylinder.
On the passenger side it is located here:
It then runs behind to the other side joining the pedal box
Bit tricky on the glovebox side (not much space to work in) but 17mm spanner gets the job done. Undo on the steering column side as well and as mentioned, use pliars to rotate the rod clockwise (if looking to the right). Don't do it too much or the brakes will be applied without any pedal pressure! I did wonder why the car wouldn't go anywhere, so it's a little trial and error trying to find the best balance.
Brakes feel quite a bit better now. The bite is much more immediate and less pressure is required to obtain the required braking force.
