Skylion.
I think you will find that the rest requied on long range flights is set by the CAA and not something insisted upon by the union.
It may well be that other airlines flying under the flags of other countries may work to different agreements but I am sure that most have a similar system. On long flights there is a legal requirement to have a certain amount of bunk rest, depending on the flight length, in order that the flight can legally be that long.
I think it is great that you all take an interest in BA and it's crew but I find the level of mis-imformation very high. Sometimes it seems like people just think something and then type it out as if it is fact, not really having enough detailed knowledge of the subject to do so.