Louis - I mentioned a couple times in PMs to your threads to PM me - I will just send you 4-5 if you want to try to modify the 30 cal links. Send me your address, and I will drop a few in the mail. I had a lengthy email back and forth with the guy in the UK selling the "Lancaster" links. He is firmly convinced that the Spitfires and Lancaster powered turrets use 1919 Brownings, in 30 06 , and the links will work in 303 ... Sent him photos of the guns and links ( I posted those here too), he was still convinced because his buddy told him they looked like 30-06 .....
You can modify the DAQ links to hold the 303, but My experience has been that the high speed feed in the MKII causes the ammo to fall out of the links. Let us know how the project works - We may be able to jump off your work !!