Send a message to the person who requested a photo of the grave monument of William Boak with the following comment:
One of William's Boak's sons, George Rennie, married my great, great grandmother Susan Julia Hyde (nee Morris). I am writing a family history at www.charleslister.net and would like to include this photo if possible. If in exchange I can help in any way please let me know. I expect that at some point this year, I will be visiting some London churchyards as part of my ancestor hunting.