Yes, it would likely take years to fully mobilise and have a reasonably high percentage of combat ready units.
As for equipment, we've probably got enough small arms (rifles and machineguns) to do the job already, even if many reinforcements would be armed with older equipment. Heavier weapons (40mm grenade launchers and up) are another matter. That was the case in the 41st anyway.
Technically every officer and machinegunner (plus a few others) were supposed to be issued with a pistol as well as their main weapon, but the armouries of the whole battalion had a grand total of just 7 of them... I don't think they ever even saw the light of day.
On the other hand BHQ armoury still contained at least one .55 Boys AT rifle, and my own Company armoury had two .303 Brens, along with three Martini Henry rifles left over from about 150 years before! The Brens might have seen service again if the shit really hit the fan, but the rifles?
