Yeah thanks Russ I did flick through that and it'll be great to have, i'm sure i'll use it again
Just didn't have diags of the piping, but got some guidance off EBay visually. I've found the issue anyway, plastic degraded on the heater valve and the tang for the hose snapped off, being on quick release fitting at the other end it just flopped down the bottom of the firewall giving a misleading picture of where it'd come from. New valve on order for stuff all, 1/2 hour job an she'll be back on the road. And the heater will be working