Eric: Many thanks. This helps put things in perspective.
Knowing you are a Bölkow man (from our days in Africa) BEAS had a 105D in their stable (G-AZOM) also 'on lease' or flying 'under convenience' for Bristow. This was the 105 which ditched off the coast of Skegness in July 1984.
You mentioned G-BALZ .. and here is one of her compatriots:
Bristow Bell 212 G-BCMC as seen at Aberdeen's Dyce Airport in August 1977 (Photo: Martin Harrison)
This "Master of Ceremonies" was with Bristows from August 1974 until August 1999 when she was sold to Spain to fly as EC-HFX. She was finally sent to Peru (where I believe she ended her days) flying as OB-1972-P.