If you state the name of the plan I may be able to look up the plan No in an old handbook.
The plans should still be available from Magicalia in England
www.modelflying.co.uk who have taken over most of the MAP/Argus/Nexus/Highbury/Encanta magazines.
Those designs that were discontinued by Nexus should be available from X-List plans
www.xlistplans.demon.co.uk. If you download the pdf file catalogue you will find more info than on the website
All the construction plans should be available from one of these sources. However the 3 view scale drawings may be owned by the publisher of the Aircraft Archive series.
Note that the Aeromodeller magazine was sold to another publisher and is now part of Aviation Modeller International magazine published by Model Activity Press.
www.modelactivitypress.com But I think the plans were not sold but possibly the 3 view drawings (not construction plans ) are with AMI. Anyway the AMI mag with Aeromodeller inside is in the bookshops in England now.