Employment Contracted Hours And Overtime Payment

[BigRooster]

Hopefully some one might be able to answer this question .
I'm contracted to be at work 5 days a week 4 at 8 hrs and 1 at 7hrs which works out at 39 hrs .
In my contract it doesn't state the start and finish time it doesn't even say when overtime will be paid .
In the 15 yrs I've worked for the company if there's no overtime then it's a 8 till 430 day but at the moment I'm doing 530 till 6 .
on the time sheet we fill out are selves it states that overtime will only be paid when the contacted 39 hrs are reached .
So doing the overtime by Thursday at 9am I would have reached 39 hrs and could go home ?
or could I be made to work the final 2 days as stated in contract .

[fiction-factory]

Wold you rather stop after 39 hours or work Thursday and Friday and get plenty of paid overtime. The company probably needs you Thurs/Frid but you need to check with them. With hindsight it'd be better to clarify things before working such extended hours, and you certainly need to clarify it before you consider putting your coat on at 9am Thursday and saying "see you next week"