Arthur's brother should be called....

[ChittyBB]

Wilfred (nn Fred)
Hector
Max
Fergus
Thomas
Samuel (nn Sam)
Jack (family name)
Lawrence
Humphrey (I love this but don't really have the guts to use it)
Byron (family name but I'm just not sure that it isn't cheesy)

Sidney
Cecil
Vincent
Cedric
Seth
Laurie

I thought Wilfred before I opened the thread. I also like Laurence. Or Leonard? Walter?

Gilbert nn Gil is very cute.

I am campaigning hard for Wilfred at the moment. DH is all about Jack. We meet in the middle on Lawrence but neither of us love it. I'm a bit unsure about the nn Laurie.

Going back to the Bertie suggestion what about full name Hubert (very old name hardly heard these days) then if Bertie hates Bertie as a teenager he could he'd have the choice to be a Hugh or Huw if you want the Welsh spelling.