Hi Andy, welcome aboard, you can try Dave Keough at
www.Pandanmodelboats.co.uk He's a nice guy and I think he used to stock them. I contacted Modelbrass a while ago and they did reply to me, but as I said it was a while ago...Just to wet your whistle so to speak, have a look at some of these sites, dream-arts.de a German site that makes upgraded conning towers at 1/35 / 40 scale beutiful, also Accurate Armour based in the U.K. they do a tower at 1/35 scale exquiste stuff. Hope the above is of use. If you need more advise about the conversion PLEASE ask BEFORE you glue stuff in. There are a few mods to make which need doing at the build stage all easy if done at the right time. Good luck.