Ah, I just realised something.
The ceramic bulb is mounted at the left side, however it is not right at the back wall of the viv, but is more centred.
Is this a big problem? I realise now that if the thermostat probe is glued/secured at the back wall in line with the bulb, it would not receive the heat as efficiently, and the bulb will heat more, making more potential risk of burns.

Would it be okay to somehow position the thermostat probe in such a way that it is closer to the bulb? Or perhaps it would be best to unscrew the whole thing, bulb mount and heat guard, and reposition at the back?

I will post a pic tomorrow to show what I mean, but you probably get the gist of it.