You could try Williams they market one which is maybe made for them by Simon, not 100% sure on that but customers have been happy with them.
I have a Mulfab in my Plus 8 and that is a well engineered efficient unit as well, so you have options.
Correction the Williams units are manufactured by Mulfab to their spec.
Simon seems very busy at the moment - https://www.facebook.com/SiFab1874/?__tn__=%2Cd%2CP-R&eid=ARAM1lbjgqYjHhp4E3JjBt2-YtUuTdURtFIep8fNJAvWDEzhehO813MK6qS6H2W2YqMkQFNMrwz3kDGW
