Got answer from Coventry today.
The toolholders are custom made for Boxford.
Production stopped in 2012, but they can make them at 156£ each with the groove. However, i strongly belive it's the same as their standard Easychange toolholder(without the groove).
I will order 1 and check similarity with the ones i have. For nearly 60£, i could could even fix that groove myself in my lathe.
The pullstuds however is a Boxford product according to Coventry.
Will have to make them myself ��