(though not looking forward to bleeding the brakes again as it took ages last time to get even a firmish pedal).
If you have the normal 'rubber' type flex hose from the Subframe to the Trailing Arm, you can safely pinch off the hose before disconnecting it with a tool like this;-
https://workshopping...-brakefuel-hose
It will save loosing all that brake fluid and when it's all fitted back up, it'll take 2 or 3 pumps of the pedal to get it back where it was.
I have a few of these tools and routinely use them when servicing the Trailing Arms and the odd time I remove a Front Brake Caliper.
Don't use these though if you have Stainless Steel braided hoses. If you have them, then after disconnecting the hose from the Trailing Arm, cap it off with something like this;-
https://www.carbuild...le-blanking-cap
Many thanks for that. Never seen those despite many years tinkering with cars. I will get one in case I need to remove the arm.
Just a thought - if you replaced some suspension parts and readjusted the Hi-Los - is it possible the donut wasn't seated correctly and so you adjusted the Hi-Lo too short (on the O/S) to get the ride height correct, then the first time you went over a bump the donut seated and the suspension was then too low (and the adjuster too short as evidenced by your jacking the car up and the suspension on the O/S being loose/free to dismantle)
I have found the rear donuts can be awkward to correctly seat on/in the locating ring - more so at the rear than the front - don't know why?
Maybe check that both Hi-Los are adjusted roughly the same amount ?
The nearside cone is tight in the seating and the bar and everything on that side is tight when jacked up. The problematic offside cone flaps about and everything is loose when jacked up, but seems to seat OK when on the ground. When I last adjusted it I went for a drive and heard a crunch from that side when I went over a bump: I think the car had risen and made that side suspension loosen, but it went back into place when back on the ground. It is as if the gap between the seating on the arm and the seating for the cone has/had lengthened, but that doesn't make any sense. The Hilos do seem to be adjusted similarly when the car on the ground and clearance is correct.
I have ordered another knuckle joint and will dismantle everything to see if I can find the problem and then report back
Once again, many thanks for your kind advice
Best wishes
Mike