@rjbull: Thanks for the heads-up on IsoBuster BDJ. Having been a bit busy on other things, I had missed the deadline but was able to take advantage from the deadline extension.
I had tried IsoBuster out on a free trial basis, but it was kinda crippled and useless. However, I read the specs and its range of functionality looked pretty good. I have just bought a licence via BDJ and am now trialling IsoBuster v3.1beta - the latter having just been announced as being "stable".