Citroen Xsara Picasso - Steering wheel wobble - xcp_owner

I noticed steering wheel wobble that started to snatch to the left when slowing down. was a bit scary so took it to nearest garage asking them to check for me - they seemed a bit uncertain what it might be, (possibly uneven tyres etc) but agreed to check it over. I was told after inspection that it needed new brake pads and discs and a new track rod end which was loose ... it was probably the play in this causing the problem. With a new tyre, new track rod end and pair of brakes costing £400 I set off, only to find that the wobble was still there - not now snatching to the left, but still there when slowing down. I was a bit worried and thought I would take it back, but after about a 15 mile trip it started to make noises when turning , then on a second turn there was a horrible 'grating' noise so I stopped. It would not go any further, so amid cars compaining with their horn, me and my passenger managed to get it to side of road. Fortunately near a local garage who came to help. Seems it's probably the drive shaft ... so I called the first garage to say something had broken, but very quickly they said it would be nothing to do with them as they would not touch anything like the drive shaft when doing brakes tyres or trackrod and that it must just have been 'going' anyway and it was just bad timimg :( My Question is - as I took it to them asking for advice on the problem - should they not have spotted this ??!! (it's fair to say the brakes were actually in need of change, but maybe not that urgently?)