What's the deal on guarantees with brake parts?!?

I bought my mkII Octavia mid-April of this year from Hitachi Lease Capital. A good economical estate car which I'd driven since 18k, and for which I got a fair price for when bought at 50k at 4 years of age. Can't fault Hitachi on the buying process, other than the fact that it's a "computer says no" situation when it comes to negotiating price!!! Oh well. Mustn't grumble.

Problem is, Lease companies seem to be cheapskates when it comes to servicing etc. Here is my case. Last winter, as we all know, was a harsh one. I got caught in particularly harsh weather with a long journey ahead. Extreme weather resulted in warping of front discs, and pads were low too. So. I had them replaced. By Halfords.

I followed "bedding in" instructions as I was told to do. This was end of February time. Since then I've a knocking tapping sound from what appears front brakes since then - and we're now in June! Sound only happens at slow speeds (under 30-40mph), I've had it checked 3 times. Twice by Halfords. One in Cornwall, one in Cambridge. They've checked for grit/movement etc. They say brakes operate fine (although I think not quite as fine as before). But brakes shouldn't make a blardy great clacking noise when braking at slow speeds! So something ain't right! Halfords don't seem to budge.

Should I take it back to Halfords? Or cut losses, deal with the noise and carry on as I am? Get AA (I'm a member) in to look at it? Just s0d it, and go to another garage to get them to have a look...even though the last 3 can't see an operating problem with the brakes?

The brake "clang" noise is driving me crackers....hence the rant!