It's the left (blue) one.
Could'nt find much on the internet and here on Mode Zero besides later proportion four channel sets. Since Horizon Systems came from Bedfordshire it would be strange if not one of the specialists here can help with filling in the details.
Questions that come to mind: what receiver and actuators did go with the set, are there any schematics or whatever any stories?
Henk from the very hot Netherlands. To hot to go flying
