Hi Phil,
The temps in TAT are correct, I read 51°C/51°C which is about right. You have a similar e6300 to myself which runs a tad warm but nothing to worry about.
If you wanna see 'real' full load temps then click both the start buttons in TAT (highlighted in red).
The heatsink gOOp needs a few days to work well, make sure you switch the PC off at nights to help it set. Also does your graphics card exhaust the hot air out of the case rear?