If it is heat that makes a difference, then it's probably not the suspension. My guess would be the exhaust as that is on the left side of the vehicle. But what about the exhaust is causing the click / clunk? There is a strap between the exhaust and the joint of the engine/gearbox which is sometimes missing and often loose. If you can get underneath (just jack up the left hand side) you can grab the cold exhaust and push it back and forth -- that might give you a hint as to the source of the noise. When you are starting off, the engine tips to the right (opposite direction of crank rotation) which might cause a clamp or strap to shift. Let me know what you find!
Hope this little bit helps. Roger Parker from the MGOC will probably weigh in on this since he's just up the road from you.
John Twist
SAFETY FAST!