When measuring the ohms between the pairs of pads all were around 0.4 ohms and the pair across that burn holes measured 2-300+ ohms, so ordered up and fitted and new armature and now back in business.
Thanks for the pointers, now to look for a decent router table / plate.
OK checked the brushes and they have plenty of length and wire / spring look in good shape, looking at the armature, there does seem to be a small hole between two of the pads see attached photos. So it's looking like the armature may have met its ends?
Thanks again
My Triton MOF001 has started playing up, kind of running fine then starting to miss like a car engine then larger sparks than normal around the armature, then cuts out and wont restart. Had a peek inside and the armature looks very black where the brushes make contact maybe due to the excess...