Notice this strange noise from front brakes twice now and cant work it out.

Its like a squeaky spring type noise when i let off or press the brake pedal when coming to a stop and only here it at low speed, prob coz its not that loud.

Doesnt do it when cold, in reverse or stationary only when been driven for 20 mins or so and warmed up.

Last owner done about 400 miles in a year so wondering if discs

/ pads have deteriorated when been sitting around for a long time? Have taken the wheels off and had a look and the brakes dont look pretty but they perform ok.

Pads not low but i think discs could be needed but surely cant make this sort of noise? Any ideas guys? Rev 3 Mk2 NA