already did that before i posted and tried everything without much change.
after digging about i found some references to the WORKSTATION service, which on my system was set to automatic.
disabled it and now everything runs in line with only the gap at the start to the point where explorer.exe kicks in and the mrxsmb entry that was taking seconds has merged in with everything else and the process creates are complete within 30 seconds

.
blackviper indicates that workstation should be left as auto, so will keep an eye on it but so far everything is working fine.
will carry on looking around to see if i can come up with any other useful info tho.