Heya. I replaced mine.. It's easy enough to do, just used a small knife to pop it out, then it has a connector on the back, similar to the ones on the back of the ford ka stereo! Just plug in the new one and its all done!
I was originally quoted £87.50 from ford for a new analogue clock.. Very shocked, thats without fitting or VAT, nothing special about the clock, just your bog standard non digital ford ka clock..
So instead, went onto ebay and found one which lights up for just £25! Very pleased, looks great at night time, and it works most importantly :)