Arrow 5, thanks for Phil Smith's mailing address. I've posted him a letter to get a price on his plan for the A.E. Brooks "Comet III" of 1937.
I'd built a reduced, rubber-powered version (complete with dummy petrol motor) many years ago from a tiny 3-view in an old RCM&E. The accompanying article mentioned "Phil Smith has plans...", but no address.
The final piece fell into place with this URL (sorry, didn't transfer as a link):
It's described as "POWER PLANS, including Jetex and Co2, from SAM 35 Speaks. Compiled by Trevor Simpson. Updated to December 2006". It's a complete list of all plans that ever appeared in the SAM magazine, giving month, year and page. It's alphabetised by model name but searchable by designer/kit manufacturer.
This is my first post, so thanks to all the members of this group for inspiring me to get back into it.