Well after putting up with warped discs for long enough and after failed attempts to avoided changing them by servicing bobbins etc i finally replaced them.

Was very pleasantly surprised to get OEM discs from ajsutton for �60 each delivered and with HH pads from M and P it came to �150 all in which is less than 1 disc on my fireplace!

Not so bad after all.

Must say the AJ Sutton prices do seen very reasonable .