I had a look online and there are two versions, you have the non erp version by the sound of it.
Non ERP control pcb should be ok as i think it is just a few passive components, bridge rectifier, caps and resistors, these rarely fail i found.
You just need the non erp head motor in that case, i didn't actually realise there are two different motors for the head - or maybe i am just reading crap info online. I will have a look at stuarts (manchester vacs) page and see.
Pretty sure i always fitted the standard motor in the past on these whether it was erp or not.