Thanks BobbyT for your design Proggie and all your advice and cheers to Bruce for putting up my images.
The goal at from the outset was to design a 20W or so amp for 1.9MHz as it's a local net frequency here in Bristol and although I initially was going to use class C after reading up on the web and finding this forum I decided class E was the way forward.
I had initially tried the choke model but after exploding many a capacitor (ceramics and mylars) I was informed that using the transformer method may be better, the caps being less in value and therefor cheaper (500V S.M.'s).
The driver has always been a 4427 driven with 14dBM from a sig gen via a 1:4 transformer, less drive gives poor circuit performance.
Output waveform is near ideal (square) as the 510 has a low input capacitance, you can use a 530 here to as I'm sure it'll be a bit more robust but I found the 4427 got a bit warm and took nearly 4 times the current and the waveform not as good (not really a problem). I initially used postage stamp trimmers and the output inductor is 30T on a T200 toroid, you can adjust the inductance by squishing the turns around the core.
The values are all measured and compare vary favourably with NU2B's dos prog. I wasn't too sure about the output inductor as the value looks a little low
(calc = 17u4) but have used a higher value for C2.
560p and 18u2 are closer to the calc'd values (583p & 17u5)and model well but didn't have the right cap!
I have managed to fudge the sim by putting some distributed capacitance in the transformer (10p:40p) which I guess would be there although have been unable to measure this (anyone know how to do this with a network analyzer?) .................Update...............Measure self resonant frequency!
Well here it is:

Green is the FET Volts
Blue is the FET Current
Red is the Output
Grey? is the Input.
I'd appreciate any comments especially from any UK hams.
Thanks again to all.
Regards.
Oh and next a low power class H mod!
Ideas anyone!
Stretchy
p.s. to get more power, more volts! 28V will give 30W or so but be warned, V Peak (3.6 * 28)is at the 100V rating of the 510, I'm sure the FET is under rated but you can see the waveform crimp with a few more volts! The transformer also gets a bit warm! So you'll be wanting to run this thing at 12 - 14V (5W-8W) carrier OK.