No Don i believe you go back to the rank of Pte on a certain level and then start again. Amazing lobster i think it could be subjective yes...however you can only join once you have served, therefore surely it would reinstate a career with all the same entitlements? holiday, pension etc.
Yes there are vacancies for MPGS so they are recruiting. Regardless of previous rank you join as a Pte soldier (Level 4 pay). Time frame - like every other trade varies from person to person and the location you want to go to.