I bought a Tortec Rear pannier for a bike with disc brakes, it wouldn't clear the avid BB5 caliper.

So I swapped it for a Topeak Supertourist DX Disc today, got it home and the bits that connect to the top of the seat stays are missing, then to add insult to injury the **** thing doesn't clear the QR on the lever side!!

WTF am I going to do now?

Well – go back to the shop and get the connectors. Then take a small metal file to the big square block on the bottom of the rack. You might need to shave off 1-2mm if the holes for fitting at are very close to the QR (yes – I've seen this before).

I was going to get the bar thingies.

Thats not going to affect the stability of the rack is it?

should have got a tubus

Shouldn't do if it's only a couple of mm. off the edge nearest the QR. There's plenty of "meat" on that bit of the fitting.

Nice one, off we go with a file he hee