Brakes are a bit rubbish.

[Tom]

From what I was taught at college, when pads aren't bedded in properly and used too hard initially, they glaze, which is caused by the hot temperatures between the pads and disk pulling the resin from the pads towards the surface. They need a gradual introduction to heat to prevent this.
Yours clearly have suffered this, and my guess is the the damage is too far gone so it's just reoccurring all the time.

I'd say get new pads.

This is what i always thought, but the bedding in procedure comes from Ferodo themselves about roasting them on the first go