MXL Pulley supplier UK


My Z axis is losing steps, and the only cause I can find is that the motor and ballscrew pulleys are very worn.
The pulleys are mxl pitch, and are 40 teeth and 80 teeth.

I can find some on the net, mostly 1/4 inch deep or 10 mm, but these are 25mm deep.

Does anyone know where I can buy a suitable replacement, I am in the UK. I don't need an exact size match, I can always machine away an oversize pulley.

Many thanks