There's an article in "Rob's Web" which set me on this path. See :
https://www.robkalmeijer.nl/techniek...e32/index.html
This refers to a piece in "Ham Radio" magazine November 1989 written by VE3RF. This uses a pair of MPF102 JFETs and is probably where I'd start off. (I'm not looking for a design to copy as I want to use the project as a learning experience).
I'm not aiming to be too retro - no valves - it's to drive an early solid state Racal manpack (Squadcal) which was crystal switched rather than synthesized. I want to keep to the spirit of the time, so no digital synthesis. That's what I have at the moment - I'm using an HP3325A which works great, but is a sledgehammer cracking a nut in this context !