Many thanks for your swift reply. I realised that operation would be slow, but I just wanted to see how the new features of Version 3 worked and whether there had been other improvements. I tried Version 2 and really liked it and thought if Version 3 was better I might actually make the jump from LR/PS and upgarde to Mojave at the same time. The thing that *REALLY* impressed me about RawPower version 2 was the responsiveness of the sliders when making adjustments. So many packages are too slow and take too long to render the changes.
I’ll perhaps setup a second boot disk with Mojave and then try again.