Hi Johno and co,
Thanks for the kind comments and whatnot. I've been watching your build(s!) with interest too, at the rate you're going I'm going to be looking to you for ideas and help before much longer!
I've got my sump 40mm below the bottom rails, and bonnet clearance is borderline, so at 50mm you should be alright.
I don't mind you using my dimensions at all - just don't blame me if it all goes horribly wrong
If you do find the sump mod link I'd love to see it, as there's some evil bumps round here too. There's a particularly nasty one guarding one of my favourite 'scenic' routes to work. I used to grind the MX5 out every time I went over it, so won't have much chance in the roadster
An East Anglia meet up sounds good when we've finished building, I'm aiming for spring 2013 if you want to pencil something in the diary!