I flew ARDU Mirages, amongst other types, from Avalon in the early '70's. Don't recall ever being speed restricted.
Tulla was being built during part of that time, but I recall doing a PFL (Mirage) shortly after it opened. A Mirage PFL included best glide speed about 300kt, slowing to gear extension speed 240kt then accelerating to max speed gear down, 270kt, IIRC. The time taken for clearances was such that I never bothered again. Certainly didn't practice diversions to Tulla in any of the 7 aircraft types I flew there.