Help identifying unknown drive WC5-20LM

Following an unfortunate accident I have to replace one of the drive units of my Clements Reference 1 loudspeakers which now reads open circuit on my meter. The only indentification on the drive that I can find is the designation WC5-20LM painted on the back of the unit. The units are 133mm wide.

Pictures of the unit are available here
picture of rear
picture of side
picture of front
Any replacement will have to fit the existing mounting holes and front pannel rebate.

I have looked at drives from a variety of manufacturers and the one it most resembles is the Monacor SPH-135/AD .

If anyone recognises the drive I would welcome their input.

Neil (J Mackie)