Murphy went for a check-up this afternoon and to have his eye's checked again with the schrimer tests which measure the mm of tears produced. In his dry eye, it is still zero, and in the other eye its about 5mm, but it should normally be 15mm. The vet also said Murphy's heart murmur is grading up to around a 3 now.
I am taking him back on Monday, for a full heart check (blood pressure etc), which is free, but only avaliable to dogs which have heart problems or could have.
The vet said I could try him on medication for two weeks, to see if he comes out as a different dog, and if he improves, Murphy will start medication.

I hope you are all well, and cavi's are well.