Re:the clunk noise just after starting. All the advice has been on the
money--worn splines are a serious issue, as are loose/worn u-joints. But
don't ignore the (possibly) obvious. Also check the tightness of the U-bolts
fastening the springs to the axles. As little as a quarter-turn slack and
these will give the axle enough room to twist slightly when you start off,
producing a clunk noise. Similarly, the bolts on the shocks can do the same.
Tighten, tighten, tighten.
60 BN7, 55 100M, 72 BGT, 88 XJ6