For those that might be interested
now carry Oxygen generators
Producing 5 LPM @ 7psi
Run on 110 60hz
Weigh 53 pounds and cost $400.
They are refurbed and upgraded medical units.
Their suitability to your individual needs is you'll have to figure out yourself.
This probably has the greatest potential in helping the UK folks with their bottle restrictions provided their budget can absorb the initial outlay.