I had a similar situation a couple of years ago. 2700 hrs gazelle, no check ride/currency, 485hrs Lynx current. Unfortunately, as you pointed out;
"Current CAA/Mod agreements state that to get a miliary type rating endorsed on the licence you have to have 500hrs on type AND a current check ride in the last 12 months."
"I currently have 420hrs on 212's ...."
The non military QHI issue isn't the problem as it would be an official 'check ride", however the hours would be.
If you have 500hrs Gazelle or Lynx, I believe you'd just need to speak to your friendly standards chap and arrange a 'check ride'.
Fortunately for me, linkup paid for my rating, perhaps that is a route if you have FRI or suchlike.
Then again, 212s = posting with lots of LOA!
ATB
SS