Eric,
I collect and restore Lister engines, as Jason says D's are cheap but prices are rising, for me to get you a good idea I would need the spec no and serial no as engines which have spec 11 to 13/14 can fetch in good order upwards of £200 to £300 pounds, un restored runners, spec no 20 and upwards £50 to £100 each. you then get type A, B F, G, H, J, K, L, M, N, P, Q, R and X if its an X the price will go off the scale as very rare, there is only a known couple in the UK. All the other types can go between £200 and £1500 – £2000 depending on condition.
I've just come in for a cup of tea, I've spent the morning stripping a H type ready to repair and show at rallys this year.
Can you copy advert as I dont get ME.
Martin P