There is a good reason why that spare pendant accelerator pedal exists.
For the pendant throttle pedal, providing enough cable movement and also having a good cable routing is quite an engineering challenge on the RHD Hawk.
A floor mounted pedal is usually the alternative/solution.

I noticed the Lotus Elise has a clever mechanism for its RHD pendant throttle pedal/cable arrangement. I'm sure a version of it could be used on Stratos replicas. I'm pretty sure it could be geared up or down too.