Am flying soon into Manchester, train to Penrith - does anyone have any idea where I can buy gas cartridges for a 'Pocket Rocket' in Penrith? They need to be the 're-sealable' type. Can't carry those on the plane, and from Penrith I want to catch a bus to Threlkeld, to begin my 6-day trek round Lakeland, up Clough Head first (depending on the weather, of course!).