Soft brake pedal for first push then stiffens up?
 

When going on the middle pedal the first push seems to be filling the cylinder and the second I can feel the brakes a lot more. Is there anyway to help with this, is this air in the system or just normal?

Air in the system or old fluid - sounds like they need replacing and/or bleeding. I presume the level is ok in the reservoir? Do you know when this was last done? Most suggest that this should be done once a year, but my model (MY02 WRX) has a service schedule of 2 years for replacing the fluid (and hence the bleeding).

Sounds like air. If you have rubber hoses you may also have a split on the inside of the pipe. Fills up on first push.

The whole system is in need of flushing and refilling so old fluid is probably the cause. The BIG service coming up soon and think I can live with it as it is for now.

Thanks for the replies guys.

Would old fluid become compressible?? It will likely have loads of water in and boiling point will suffer so may give up when it gets hot. But can't see it causing the symptoms described.

Similarly with air in the system, that would make the pedal spongy all the time, can't see it causing the symptoms described.

Surely the only thing that makes the pedal long the first time you use it and then it comes back is pad knock off?

That said if the fluid is old it's worth replacing it and it's relatively cheap to do so probably sensible to do it anyway then look further if the symptons persist.