It's either a stupid/obvious or a sharp intake of breath problem, but....

1.5 M-Reg AX diesel churns forever (a couple of minutes) before eventually
coughing into life.
Pre-heat system seems to check out - plugs are all good and heat up OK when
out of the car, timer keeps them on for the requisite period, and the
battery is new.
Can't be fuel or air supply per se, as it runs superbly once it is coaxed
into action, and once it fires up there are clouds of evidence of fuel
getting in!  Re-starting from hot is fine, but the following
morning..........
I suspect something to do with one of the more obscure controls on the pump,
but if anyone has any more straightforward suggestions I'd be very glad of
them!

TF

(PS Why do Haynes AX manuals show you how to strip a gearbox, but not how to
change the dashboard bulbs?)