Such a drag

Afternoon all, been a while since I've been on. Slight problem with brakes. Year 2000 P38, I put new discs, pads and calipers all round about a year ago and been through two MOTs since. The problem is I feel a slight bit of brake drag, not really when driving but when I pull up at traffic lights etc and only shows up when I slip it out of gear and let it roll to a halt. I stress that I only do this to check for drag rather than as a matter of course when stopping. Sitting cold it's easy to push the car back and forward without any squeal etc from the brakes. MPG isn't really suffering too badly, getting 18-22 (V8 no gas) it's just that the discs feel a bit hot after a run and the black dust build up on the wheels. New brake lines front to rear so the system has been bled. I did hear from the workshop controller at a local main dealer that there is an electrical back up system incorporated in the brakes but rather than let him baffle me with science/ bluff to get rid of me I thought I'd ask an expert on here. Any ideas or should I just be thankful for 22mpg? I've had a search re bleeding brakes and been through all the front/ rear/ master sequence.

Thought with the thread title it was about cross dressing Range Rover owners

Cant offer much advise for the brakes, other on here will be along for that. 22mpg on a V8 is good going though.
My rear diff was causing similar symptoms to yours though before it started to be obvious.

There is backup if certain systems go down. But it does not put the brakes on for you if you forget to. So he is bull****ting. Only thing to do is take a look, lift each axle and check for dragging. Don't forget the hand brake.

22mpg is good, best I get is 18 from 4.6 V8, when I bought mine one rear caliper was sticking although jacking it up when cold did not reveal the problem, jacking up when hot did.

I did suspect a bit of flannel from the 'controller' or 'cantroller' to be fair. Handbrake drum is always cool so that's fine. Think I'll jack up each end in turn once I've had a decent run ad try that. Who knows, a new (recon) caliper could be sticky but it's all four discs that heat up. Not the calipers though so at least it's not a real bind. (Had smoke from a Jaguar rear disc once which the dealer said was ok. I freed it and the others off and got an extra 5mpg out of that car afterwards). Will report back.