"Bif" Semi-Tubular Rivets

I’ve been doing some digging on “Bif” rivets used in Hawker construction, and have found two different call-outs for them. In the Tornado-Sea Fury types, drawings always refer to them as “Bif H8” or “Bif H10″; and my understanding is that the numerical designation is the fastener length (yet to be confirmed, but it appears that both types of locations are 3/32” fastener diameters). In later Hawker designs, as indicated by a 1960’s copy of the Draughtsman’s Handbook, “Bif” rivets are called out as either LAR 162 or LAR 163 “Bif Rivets”, when called out in this fashion, they are followed by a “/11” value which again appears to be fastener length. Eg. LAR162/11. With this later type designation, the material specification is called out as L.69, which has now been superseded by L.86.

So far, I’ve not been able to determine the material specification for the earlier “Bif H10” style rivets, nor have I been able to locate a cross reference that can confirm that the newer style superseded the older style. I’ve seen that typically L86 rivets are installed for restorations of the earlier Hawker types in lieu of the Bif rivets, but am seeking proper reference for this one.

Can any of the wonderful folks on this forum help me with this issue?