Look very carefully at the location that the trailing arms mount to the frame. This spot is very easy to get to, it's just behind the seats, and underneath the car. If there is rust on these pieces, get up, dust yourself off, and say 'Thanks, but no thanks'. Talk to you local British Car Mechanic about getting the mounts repaired. They can fail.
Failure often results in major differential failure that is remedied by replacing the diff.
Farm the work out. When they start to get tired, they can be easily reconditioned by a competent overhauler. These are the biggest failure point. Replacement can require a different crankshaft and block if the condition is severe enough. To check, simply push the crankshaft pulley rearward as hard as you can, then have an assistant sit in the car.