Is it possible to get cradles for a bike engine that will fit chassis built from specs outlined in the book??? Or will i have to make one myself

I fitted a Stuart Taylor blade cradle when I first built my Locost, but I had to move the top diagonal chassis tube to match up to the two cradle arms, the one that runs from the top offside corner of the transmission tunnel to the front of the chassis just behind the top damper pickup.

I doubt you'll get anything off the shelf that will just bolt in, but if you're OK doing similar to what I did Im sure there's probably several options from places like MK etc.

Just make one yourself. The cost of buying one from the manufacturers, to then have to modify it, seems crazy. Just get some 1" tube, and get the welder out!

Yup I should have said that really, when I converted the R1 I fabricated my own and it was just as easy.

FWIW I didnt need to mod the STM cradle for it to fit though, all I needed to do was leave the welding of the diagonal chassis tube until after I had the cradle so I could position it accordingly as opposed to exactly where the book has it.