Well I have to admit that I've not written too many letters to Chairmen of Select Committee's or Ministers of Government.
I have however had meeting with them on more than a few occasions and do know how the Parliamentary system works.
I suggested the Chairman of the Home Affairs Committee because it's is he that controls what that committee does in regard to firearms. Writing to any "Minister" will sometimes not even elicit any form of reply, but if you write to your M.P. asking them to pose a question to a Minister on your behalf the Minister has to reply to them.