Nested VLookup in an IF Function

At the moment I'm trying to create a timesheet which will pull up an alert if a candidate has worked more than 45 hours and also hasn't signed an opt out. It's spread over a couple of worksheets and at present I can't seem to get the functions to work together. The formula I have at the moment works out as:

=IF('Data Entry'!E4>=45,VLOOKUP(B8,Source!E:H,4,"NO"),"This candidate has exceeded the Working Time Regulations and has not opted out, please contact The Academy."," "))

I have attached an example of how its set up

It will be going onto Sheet "Manager Entry" in B16 (in place of the coding currently in there)

Thanks, but it doesn't quite work. The end of the code you've posted isn't quite right, so when I corrected it it told me that I had too many arguments in the function.