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