It turns out that is a very simple solution to this problem. It occurs because the Veritas software is trying to connect to a network resource that is slow in opening - in my case a NAS system. You make a simple change to ta settings file and VSR 18 SP1 is immediately operational - once it has managed to connect to the network destination. (if you open the network share separately using Explorer that allows VSR to also connect there just about immediately instead of it being quite as slow.) See
https://www.veritas.com/support/en_US/article.TECH224990 for the details of which file you need to change. Thanks to Veritas Support for coming back with the solution very quickly. Very impressed.