I presume you meant "you USE a hydraulic handbrake"?

The std handbrake is cable operated, there is no reason why you couldn't fit a pair of mechanical handbrake calipers to keep it legal. Although it would be alot easier to just use a hydraulic handbrake, and take the car to a "freindly" MOT tester, if you know what i mean

Sourcing mechanical handbrake calipers is the problem, you can use RS200 items, but they are very rare! Wilwood do some, but they don't fit straight on, brembo do some but i have no info on these, so hydraulic would be the easiest option.