Thank you both for the replies.
I think I was thinking that the extra pull of gravity would come into it somewhere.
I have had a look at wiki and seen that the speed of gravity is theorized at being the same as the speed of light. I had assumed the gravitational force was instantaneous.
I know from my physics lessons many years ago that a gravitational field can bend the path of light, but what is the effect of gravity on a photon when it is heading directly at a star. "If" the speed of light cannot be exceeded, what happens ?