Dash lights revisited

Hi, the lights in the instrument cluster on my 1987 W126 300SE do not seem to work, neither does the light that would normally illuminate the
gear lever. The reostat makes no difference and there is a warning lamp
on the dash for a burned out bulb. I think that the light is telling me
that an exterior lamp bulb has gone and it is nothing to do with the dash board/gear stick. It only comes on when the head or side lights are on. You all kindly gave advice on the assumption that you are able to physically touch the pod that houses the dials. Unfortunately you can't. This is a UK car which may have confused matters.
I got a chance to look at the dash today and I was expecting to see a similar push fit to my 1981 W107 with gaps in the side to put the
keys/hooks but instead I am confronted a sloping piece of plexiglass to
cut reflected glare and no visible way in and no gaps or anything. Do I go in from underneath at the side of the steering column.?
Thanks Jim

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