Sorry it's taken a while to reply, been out of the country. The parts I bought and had fitted by my local garage (G&R Motors in Woodchurch, Nr Ashford) were :
Anti roll bar (torsion bar 203 323 43 65) complete with "manschettes" (rubber bushes) and "retaining straps" 203 323 27 40 (2 off).
Rod 203 320 28 89, 2 off (the thing with rose joints either end).
Arm 204 330 43 11
Strut 204 330 44 11 (same as "Arm" but other side)
Bearing 204 333 10 14 (2 off)
Cost £275 from Gareth including next day courier delivery, plus £115 for fitting. Nick (G&R Motors) told me that was 4 hours labour plus VAT - can you believe £25 per hour in this day and age!! He knew what he was about, it was not the first W203 front end he'd had apart!
The anti-roll bar bushes were the probable cause of the knocking as they were shot. The lower arm bearings were also well on their way out so could have been contributing to the knocking. Rose joints on the rods were still OK - not bad for 70K Miles!
This has made a major difference to the car - no clunks, whisper quiet comfortable ride, and no earache from SWMBO in the passenger seat!!
Not so good was that, in taking the front end apart, Nick found that the discs and pads were shot and needed replacing. Looking through the history file, they were first replaced at 45848 miles on her 3rd MB service, so less than 25K later they're shot. I've only had the car 6 months and 3K miles, do not use the brakes hard and am only 2nd owner - so I wonder why the original shoes/pads lasted nearly 49K and the replacements only 25K.
Anyway, we're well pleased with the car, especially now (thanks to this forum) we've cured the knocking from the front end.