For about 5 years I have always obtained Replens and Sylk and (more recently) the water-based version of Yes on NHS prescription in England.
The relevant codes your GP requires for Yes water-based lubricant are as follows:
6 x 5ml pre-filled applicators PIP code: 345-5805 and 75ml tube PIP code: 345-5789.
If, like me, you're not able to use hormone-based products, or for some women perhaps need non-hormonal lubrication in addition to other products, I don't see why a GP wouldn't prescribe it. Please ask, ladies.