Thanks for feedback folks.
Seemingly it's fine if you are the only one on line.
Unfortunately the 'broad' band up-link can be very slow.
And the exchange is a long way away from the shack.-
These settings are applied:
buffer - count=16
Not sure what else to do - except perhaps reduce the number of users from 4 to 2.
Inclined to leave the gain adjustable at present.
Sadly the server may not be a long-term proposition if the signal continues so choppy.
Not until satellite gets a lot cheaper or we get a microwave link to the island anyway.
Will the HF+ take more or less bandwidth, I wonder.
(Note to self - order a velvet cushion and gold plated USB lead.)