try 'williamson pumps' same pumps £50 cheaper;
0845 2263638
or 'woodbridge' 01279 422220 are generally cheaper on pumps and vac motors.
i think its the 135 psi flotec pumps in that machine, take the bottom off your machine they'll want the number on the front of the pump, (i have seen on some machines pump sticker on outside of machine which is handy)
you probaly find it came from williamson pumps but machine makers take the sticker off so you buy it from them at a mark up.