Of course they get billed! Do you think that NHS EBME departments work outside for nowt? There's enough resistance (from within the departments) as it is. Get real, Neil.
Apart from that, let it be said that those who labour on the Dark Side
are quite happy that (in general) most in-house NHS biomed sheds are disinclined to venture outside of their own cozy little world.*
Also ... why should the tax-payer be subsidising such ventures? "Unfair competition" is the phrase that comes to mind.
You want more? OK ... (and for example) why should I (as one of the tax-payers) be paying not only for my own test equipment, but for that of my "competitors" as well? I'm sure you catch my drift, there, Mate.
* See earlier (historical) posts that have touched on this.