The problem with clocks from eBay is that they'll have faulty stepper motors..
but anyway, as long as the fuel gauge and the rev counter work, you'll be okay for a while.
The steering column shroud needs to come off. Remove the lower piece from the top piece (3? small allen screws) and then wrestle that piece out of the car by manouevering it clear of the lever that adjusts the steering wheel height. Technically it can stay there.. but it's in the way and it'll get on your tits.
The top part of the steering column shroud is attached via some screws to the column.. and these will now be accessible. There are two immediately behind the wheel (symmetrical on each side) and one further back that's randomly placed. The plastic tabs are fragile, so resist the urge to lift the shroud for a better look.
Then you need to remove the fillet from the top of the clocks. It's a skinny piece of plastic that fits into the gap between the top of the clocks and the dashboard. It has two screws (one each side) and then tabs that fit it into place. From memory you need to somehow lift the tabs up (they locates on notches on the clocks) but without levering against the edge of the glass (or you'll crack it).
With the fillet out and the shroud off, you may see two more screws on tabs at the bottom of the clocks (one near each corner). They're the easiest ones to remove.
Now you have to lift the clocks out, clear the various tabs and notches holding them in place and pull them loose. If you get a flat bladed knife it's easier to feel your way around to where the various tabs are. I think you need to press down at the top, while easing the clocks out, but without snapping the bottom tabs as you rotate the clocks outwards. I've broken them all ...
When the clocks are out.. the leads are thankfully very long, so plenty of space to remove the connector blocks. They only fit one way, so no need to mark them or note their positions etc.
Then lower the wheel and feed the clocks end-first throught the gap between the wheel and the dashboard (easier said than done).
It's a proper Mo-Fo since you will likely break some tab, or clip etc.. but not actually technically difficult.
Ralf S.