Yep, I am running the Jessie version of DietPi.
No problem - I tried the Linux Dash on one of my other Pi’s and that seemed to work fine, just that RaspConfig looked quite interesting.
I guessed it may be an issue compiling it on the new version of Debian, so I am not too concerned. I was just wondering if I had missed something myself. 
Quick edit: I have now found a thread about this issue -
https://dietpi.com/forum/t/resolved-raspcontrol-gives-500-error/104/1
and it is mentioned that the install of raspconfig will be removed from Jessie installs - but it is still there currently. Might be worth taking it out to avoid others coming across this issue?
Thanks for the swift response! Hope I will be of some use testing things in the future - I have a couple of Pi B’s and a Pi 2 as well as a couple of Zeros.
Mark