Just had another quick play.
Swapped ignition amps around and problem still the same. Weak spark on same cylinders, 2 and 4. So not ign amps.
Swapped leads. Still the same. So not leads.
Swapped leads to other side of coil pack. So 1-4 on 2-3 and vise versa. Car wouldn't start and banged. Swapped back round and fired straight up and idled fine again. Weak spark on 2 and 4 again.
Tested input voltage to centre wire on coil pack 14.6volts.
Removed wasted spark driver and re fitted. No change...
might try a new coilpack on it tomorrow and see what happens. Can always take it back I guess.