Cheers guys...got it to run tonight after gaining a bit more confidence from you lot to leave it a bit longer.
With the skeg bit sitting on the bottom of the bucket and water right to the top (probably higher up the shaft than those in the yellow buckets), it still refused to perfom. So kitchen bucket deployed for a while which was a few inch deeper and now peeing like a 20 year old
Might work shallower now as well but didnt bother trying it as we were just relieved it was working.
We have an old watering butt that will need chopping down a bit to fit under my ob trolley for a project another day which should be about right., and might also consider muffs for the future. I see they start about £10 upwards for a double outlet on fleabay...so not bad.
Ive plumbed one of my outside taps with a tmv so that the dog gets a warm hose down when her rolls in deer, fox crap or anything else that takes his fancy, so guessing that will be good to flush salt out with the warmer water.