I have to remove the wood dash trim around the trip computer on a 1994 XJS facelift car.
is there a procedure to follow?
what secures this piece? Is a special tool needed? Do I have to remove computer first?

 

There are two bolts holding it in place. I think if you remove the trip computer you'll see the heads on either side of the opening.

If not, perhaps the head is where the double button clusters are, so you'll have to pop those out.

I think I might be confusing the clock panel with the trip computer, if thats the case, then there are just two friction fittings on both ends of the trim. Be gentle, but firm. They'll come out. (These definitely exist, regardless of the presence of the bolts above.)

 

 

According to the 1992 technical introduction which is when the trip computer changed, you pull out the switches on either side of the trip computer, then you access screws thru the holes that hold the computer in, then remove it. Then you should be able to remove the wood trim.
Look on page 61 of the document at this link.
http://jagrepair.com/images/AutoRepa...XJS%201992.pdf

 

jal1234 is correct. The trip computer screws are accessible by carefully removing the switches either side of it.

The veneer is still held in by two interference pins, one at either end, on the back of the veneer which push into nylon mountings on the metal dash. With the trip computer out, you'll see how to gently lever it out from the pin mountings.

Good luck

Paul