Series 3 Can't see TDC on flywheel

Hi all, in the process of fitting a new diesel pump to my series 3, I need to align the timing mark on the flywheel with the one on the pump.

I removed the view window cover on the flywheel housing and had my partner turn the start handle round. The flywheel spins, but I couldn't see the TDC mark on it anywhere.

Is there any other way to find TDC without taking the whole engine apart? How can I increase likliness that I will be able to find TDC on the flywheel?

Thanks

You may well find it on the front pully.