Freelander Display

Hi Folks
Picking up a '99 Freelander next weekend and it just has the bog standard
Landie cassette h/u in it. I know I can get the Phillips RC 026 autochanger
to give me cd in the motor but for similar money I could just slot any other
h/u and autochanger, or cheaper still, the Sony cd h/u I'm taking out of the
Terrano that I'm part exchanging for it. BUT the Landie has the clock in the
dash which doubles up as the h/u display, so I was wondering whether the
clock will still work if I put a non OEM h/u in? If not, what is the way
around this?
Many thanks
Gareth