Vanquish S heating

[Tricky Ravenglas]

Hi all
Any ideas to save a visit down to Macclesfield. Heating on my Vanquish is just not coming through.
The temp gauge is perfect but no hot air. The fan is working and no obvious out of place ducting.

Anyone had similar?

[MarkM3Evoplus]

On the Mk1 Vanquish, the Heater Control Valve often failed causing the loss of heat - believe it is a Jag XK8 part.