Brakes sticking on

Hi

2006 Fabia vRS

Had the master cylinder replaced a couple of weeks ago. Brakes much improved.

However, a couple of times since the brakes have stuck on. Apply brakes for example on approach to roundabout. Go to accelerate away from roundabout and car is held back. When you take your foot off the accelerator it feels like the brakes are on.

Pulled over when safe and you could smell hot brakes. All 4 wheels were hot so brakes definitely sticking.

Turned off, waited a few minutes then all ok again.

It's happened 3 times now.

Car going back to garage tomorrow but mechanic has said he's not come across this before. We've used same garage for several years now.

Any ideas?

Mark