Shawbury was also the home of 11 (P)AFU - (Pilot's) Advanced Flying Unit, which was involved in training pilots, who had gained the 'wings' overseas, in the requirements and tactics of flying in Europe. This would have included air to ground and air to air gunnery, before the pilots were then sent to an OTU (Operational training Unit), and there are records of Hurricanes being based there, either for use by the (P)AFU, or 'passing through' for general maintenance or equipment fit etc.
I can only guess that 'Hurricanes harmonised' refers to the harmonisation of the guns, although this would normally be the job of an armourer. However, other 'tradesmen' would be required to place the aircraft on jacks, in a flying position, once it had been towed or taxied to the firing butts.
Sorry I can't be of much further help.