My personal chub fishing is coming on nicely.
My main issue being taking more than one fish from a particular swim.
I return all fish caught once they have recovered. I believe this is why when fishing the intimate little rivers that I do, multiple catches from one swim are in my experience nigh on impossible.
I generally use a roving approach so a keepnet is out of the question.
Does anyone have any solutions or ideas?

Tommo,

Try to release your fist fish well downstream and then try for another one or two.

After landing your first fish, feed the swim well, and then take the fish downstream for release.

Best I can think of after a decent Italian meal :-)

Re feed the swim and move come back later the fish will have resettled on the feed. How many fish you remove will vary on the swim.

When I used to fish the Leam and the Upper Ouse, I used to release the fish about 50 yards downstream.

Tommo my advice is put all the chub you catch far away far far away into say the river hull!

I caught a chub one night and released it 50 yard downstream.

I caught twice more that same night. I finally had to have a word with it for it's own safety.

I've moved 300 yards downriver and caught the same suicidal mugfish within half an hour on the same bait! Had a smashed in face which is why I recignised it so easily. Nothing to do with me I might add!

The banks can be high and treacherous. Not sure I'm that comfortable in scrambling up and down them with a fish.
How safe are carp type sacks?

Carp sacks should been banned for all fish, how would line to be kept in soak wet duvet cover.