http://www.osmotics.co.uk/categories/Fittings-and-Tubing/John-Guest-Fittings/1%5C4%22-Tubing-Fittings/One of these should do the trick, if you need other sizes go to their home page and choose 'John Guest hose and fittings' and whatever imperial size you need.
Whoops! sorry. Jumped the gun there, should have looked on the Gardiners link first!! Never mind, if you search the Osmotics site you will find what you need. If not, fit plastic 3/4" barrel nipples to the cylinder first, then the tap adapters will fit.