I recall that in the Tornado F3 we had an MDA in the Release To Service for Internal Aids Approaches using the Radar and Main Computer position. IAAs were practiced IMC on normal training sorties. They were normally monitored by ATC but not sure if that was a legal requirement?
Many moons ago before the days of "rules for everything" we used to perform a self navigated QGH pattern using Rebecca/Ureka in the Jet Provost. I cannot remember what minimums we used; about 1000ft I think?