If the Hornby controller is one of these -
- then they are a fairly poor device.
The output, particularly at the lower settings, is very 'choppy', electrically, and it may upset the more modern motor systems - possibly.
Also, they have a thermal cut-out in them, for safety reasons, but the component used for this can have very variable responses, sometimes they are OK, but I had one that could only be used in the garage, in the winter - in the house, or if the Sun came out, it would quickly 'think it was over-heated' and turn itself off.
I'm a fan of the Gaugemaster devices - fine, if you're going to stay DC - and they can sometimes be picked up second-hand, as people go DCC.
Edit - Ah, I see that the controller is one of these -
- I've never used one of those, but I wonder if it is just a 'repackaged' casing, with the original components within?