There are many different variations of mahogany so you need to look through stock to find a match, although you can use wood dye such as Colron to adjust the colour. A satin finish varnish is good to blend in with the original. I use Ronseal as it is easy to apply and lasts well down below. The section in front of the galley is profiled and it is worth finding somebody who has a spindle moulder to machine a matching profile.