The eleven bulbs are in bayonet-mounted plastic holders fitted from the rear of the panel. Replacement of the bulbs does not require dismantling of the panel but removal of the panel would make replacement much easier, as accessibility to the bulbs with the panel in situ is very tight and requires lying on your back in the footwell with hands squeezed up in the gap. The black coloured holders can be seen in the first picture below.
I did not use LED bulbs but the procedure for fitting is the same as for conventional bulbs.
Cleaning the copper-trace rear surface of the panel and all contacts is very worthwhile, so removal of the panel has the added benefit of allowing this to take place. The second picture below shows the copper-trace from my car before and after sanding with very fine emery paper. I found the dismantling of the panel to be fairly straightforward, and I outlined the steps in my forum thread "Report on (slow) S2 Coupe rebuild progress".
