I think I found the problem. The new HT leads have double the
resistance of the old ones e.g. the new longest HT lead is 7K ohms
whereas the old one was 3.2K ohms. I also noticed that the spark plugs
are the resistive type. Take all this resistance plus the voltage drop
on the systen due to cranking the engine and hey, no spark at all ! I
changed the leads for copper cored (self made) and now the car starts
while cranking instead of just firing as I turn of the key !
Brilliant. Resistive HT leads are such a pain; always cause trouble. I
think the manufacturer goes all out to reduce emf emissions which
works very well if I can't even start my car !
 Here is how I made the copper cored HT leads. The problem is of
course the fittings for the coil pack and spark plugs which cannot be
bought. To get around this, use the fittings from the resistive HT
leads. Chop the cable off right next to each fitting. Screw in a self-
tapping screw (I used a 1 inch one) half way; then saw off the head of
the screw; file or grind the end to a point and screw on the copper
cored HT lead ( you can buy this from car accessory shop). When both
ends have been assembled, I mixed up some araldite and applied around
the join to seal it and strengthen it. I'm not sure araldite is the
best stuff to use as it can crack up in cold weather. Maybe some
silicon sealer would have been better.
I have noticed no interference on the car radio; although the leads
are now copper cored, the plug caps and the plugs themselves are
resistive so this helps with supression.