Turning my attention to the grille cloth - I carefully prised up the edges using just my fingers, and was fortunate that the original glue allowed the cloth to come away from the baffle with little effort.

The cloth was very dirty and I carefully soaked it in some warm water and few drops of washing-up liquid for a few minutes, then a rinse in cold water, taking care to keep the cloth relatively flat whilst in the water.

I dried the cloth flat between layers of kitchen roll, using them to soak up the water - this method removed virtually all of the dirt and restored much of the cloth's appearance.

I found that the grille cloth was large enough for me to reposition it on the baffle with the two holes in the cloth above the speaker aperture rendering them out of sight. The cloth was reattached like this using adhesive intended for fixing vinyl floor tiles.

This adhesive works well in this situation and is water based so is easily removed with a damp sponge if it goes somewhere it shouldn't. I left the glue to set overnight before trimming the cloth.

Whilst the cloth was drying completely I took the opportunity to give the baffle a coat of matt black paint and clean and repaint the speaker with silver Smoothrite.