I think most Maritime bases had Stage 2 trainers - certainly St Mawgan and Changi and I believe Ballykelly - and Rossian brings it all back. Yes it was Heath Robinson, but it worked well and we seemed to do an awful lot of it.
Was Stage 1 the static crew simulator at MOTU alongside the Seal Bar at St Mawgan? Again it's a long time ago, but I remember doing something similar (at length) during the ground phase and we could play at chase the contact, before going on to Stage 2 during the applied flying part of the course.
It was finally withdrawn when the 1C sonar went (no point afterwards) - was that the same time as the Nimrod upgrade?