Go to you tube and you'll find a good instruction video by some guy from some magazine with guys on a roundabout. It might be an MCN piece? Very good instruction.
Its all about body position (and a little speed and lean). Don't think you have to lean the bike more and more. Yes you need a certain amount of lean, but the whole point of getting off the bike is so you don't have to lean so much. Keep leaning it over to a point beyond where you feel comfortable and you'll tense up and then youre shot.
But really my friend. Get off the road and go to a track, putting your knee down on the road is a recipe for disaster. Yes you may see people do it, and all hero worship to them, but to get your knee down you have NO margin for error. On the road you NEED margin for error, or one day you WILL die, and we dont want that. England is blessed with race tracks, please use them, please. Roads are not the place for cowboy capers (unless you're Ghost Rider, do a you tube search on that too, he is an extremely highly experienced talented rider and you must not try and ride like him)
And finally have patience. It will come. Don't force it! Dont think you are no good and not a real man (or woman). It will come. The first time you do it will also scare the shit out of you, its a rather odd feeling, but you'll love it. And remember you can still ride very fast without putting your knee down at all. (I've never seen ghost rider do it at all in fact).
Good luck and stay safe, falling off sucks.