Hi
I have two young Herman’s
The table is 4ft x 2ft I have a mercury bulb at the one end however it is quite dark in the cooler end, could I put a light in that end if so what sort/type would I need
It very much depends on the temperatures. Get an infrared temperature gun type thermometer for accuracy. If the ambient temperis 80F or higher then you don’t need any more heat and you should use LED or fluorescent lighting.
If the other end is too cold then another MVB will do no harm.
I suggest you post pictures of your enclosure and lighting so we can take a look