Can anyone help, or is this a challenge too far?

Phoenix, several years ago I had an elbow replacement, and every day I had to do a lot of exercises. I got really bored until one day I realised that the hardest exercise was similar to polishing, so I polished everything in sight! Everything began to acquire a great patina, and my new elbow excellent flexibility. The shelf was something that benefitted, but thanks for reminding me, it has been sitting in the garage for some time, so it won’t have had the same amount of beeswax

I painted a dark wood fire surround with Annie Sloan chalk paint. The only prep I did was to wipe the dust off first . It took three coats to totally cover such a dark wood and I finished it off with Polyvine dead flat matt varnish, which you paint on and is easier to apply than a wax finish that you rub on with a cloth.

It looked great.

*Lexisgranny, Lucky you have a piece to practice on, but has that had the same treatment, i.e the beeswax polish?

If not, you might not get an accurate result.

There are companies and individuals who specialise in painting things.
You could have anything, from wonderfully exotic, to plain and serviceable.

Agree white spirit and light sand will give a better key. We did this in a previous house and used a satin finish in ivory, lifted the room, no regrets.

We had an oak fire surround, now painted white when the room was decorated, looks much better!

That’s a good idea, Lexisgranny

Thank you so much for your help. I have just remembered that there is an old mahogany shelf in the garage, maybe I could give that a go first.

I would still prefer to wipe it over with white spirit and sand it lightly.

traditionalpainter.com/can-you-paint-annie-sloan-chalk-paint-straight-on-waxed-pine

Most chalk paints, like Frenchic, can be used on top of any surfaces, even waxed ones. You may need two coats. You can then lightly wax over the paint if you wish. I have done this with several small dark side tables, bookshelves, etc. I usually use Annie Sloan paint. Maybe buy a tester pot and try it on the side first?

According to google you should remove any wax with white spirit and fine wire wool. The best paint is supposedly chalk paint.