Ive just got off the phone to Williamson Pumps. The guy I was speaking to said that there seems to be a problem getting supplies of booster pumps. Well, reasonable booster pumps, that arent chinese and last a fair time.
We looked at the ones on the osmotics website but he thought those would be AC current and therefore not likely to be suitable for continuous usage.
Apparently they do have pumps at Wiliiamson that are suitable but they need to source a decent transformer. Hes getting back to me once he has. They'd be somewhere in the region of £110.00 for pump and transformer.