C - Measure length of splines. This measurement is down to the 'shoulder' sitting under the splines themselves. WRITE IT DOWN!

D - Measure from top of splined shaft to underside of widest part of the cartridge (where it screws into the tap body). WRITE IT DOWN!

E - Does the 'shroud' screw on? WRITE IT DOWN !

F - Measure from underside of 'shoulder' to end of metalwork. WRITE IT DOWN!

G - What size is your cartridge? 3/4" measures approx. 25mm across its base. 1/2" measures approx. 18mm across its base. WRITE IT DOWN!