Sort of.
And by that I mean, there is a specially designed SA80 Beta-C drum. Star make it, but I haven't seen any NIB for a loooong time (that, and they were £80...) Other drums do not fit without modifing them or the gun, because the SA80 magwell is too tall and wide (the little outwards lip at the bottom) for them to fit.
I've held an R85 with Beta mag. Completely fine, didn't noticed the extra bulk apart from when it snagged on my webbing. What I did notice was the very heavy weight of 3500 rounds in the magazine...
Before anyone says "SA80's shouldn't go near drum mags..."
Enfield and the MOD in 1981-82, under the SA80 project hired Beta-C to make the 100round twin-drum magazines specially for the LSW. About 150-200 were bought and tested. They had an extra long 'neck' that allowed the mags to fit in the magwell. However, they were never issued en-masse - by the time Beta delievered them, the LSW had changed from the XL65 LSW - which had a removable barrel and was capable of firing in long sustained bursts, to the XL75 LSW, which is what we have today (a big useless assault rifle). It was deemed that the drum mags would be of little use in the new design (barrel heat), and simply left in a store room to gather dust in the RO factory.
(From "The SA80: The last Enfield" book)