Heater problem late shape dash

[britten_mark]

I am getting no air out of my footwell vents at the moment. I have eliminated the dash selector switch (sadly) which I suppose now means huge amounts of work to get at the heater unit.

Does anyone have any experience of this to pass on? In other cars with such problems I have been upside down, seats removed etc etc all to get under the dash, I can't imagine how to do it on this thing.

Also can anyone confirm if the actuation of the valves at the heater end is vacuum or electric?? I was always led to believe that when the late dash (1998) cars came out the vacuum element was superceded. However the current Lotus surplus parts flyer (which says the valves are currently discounted) states that one part fits all.

I'm confused (and cold).