Nice car design. Just forget the performance!! I guess even my old AX can let this Rover behind with no problems!
I have no idea why you think this car is slow. I've been in one and believe me your previous AX wouldn't stand a chance. I mean a 1.4 engine with 16 valves and 103bhp slow??
I agree are you sure you didn't buy the 1.1 by accident?
I also agree, the 1.4 K Series engine (especially in Mpi form as yours would be) kicks out a tremendous amount of Power. More infact than just about any 1.6 engined car built by any other manufacturer.
Maybe get the car checked out, a Dyno test would give you some indication as to whether there's a problem.
Happy motoring!