Don't bust a gut NZL1A1. It's only a rifle blade and grips. The story I got from DH while writing the book was that Sterling only used to go to them for bayonets every now and then for small quantities. Sterling used to supply the pommels and cross pieces and the bayonets used to come back to Sterling to be blued or phosphated according to the order specification. Sterling would also fit the catches, springs and bolts and screws (all made in-house) and grips. The latter batches of bayonets came back l;ooking as they should but the grips wouldn't fit. There was a lot of too-ing and fro-ing and then it dawned on them that they were L1A1 blades, left over from ex Army contracts that were being used. Sterling weren't happy little rabbits but the contractors explained the situation and the use of the MUCH cheaper and readily available steel grips available from them (or in this case, via contacts at nearby Enfield Lock).

Sterling amended the grip spec, added the steel grips to their inventory and the rest is history........ steel gripped SMG/hybrid No5 bayonets

If you really want to put wood No5 grips onto a steel gripped bayonet, you can, but be warned, that the steel is VERY hard AND tough.