I have fitted floor mounted pedals. How much of the sierra pedal mounts can I cut off? Can I remove the cross member?

I removed all the bracketry associated with the Sierra pedal box, flush with the chassis rails.
I wouldn't advise on cutting out any chassis members as you'll compromise the strength of the chassis!

Andy.

Its all removed now... Left the two uprights for the steering and the accelerator upright. The rest is lying in a heap in the garage. Have had a look at some pics of your avon and it looks the same now.

Still cant deside where to run the rear brake down the transmission tunnel. By the book attached to the aloy pannels, at the top or at the bottom? If I were to run it down low on the top of the lowest front to back box section on the drivers side will I get round the gearbox mount?

Shades, how have you panelled the transmission tunnel? - like me, on the outside of the tunnel - or on the inside (passenger footwell) side?
If same as mine, then you have no option but to clip pipes to panelling itself or, if the latter, then, assuming you're using a ford type 9 box and sierra mounting, you should have no problem running down top of chassis rail as you suggested. (Thats how I ran My fuel line on passenger side.)

Andy.

Andy, Thanks, I have paneled them on the inside of the passenger foot well... and have now run the rear brake line down the top of the lower front to back rail on the drivers side. I cut the gear box mount off and held it in place to judge the clearance. Quite please with the results Fuel lines next. I guess the other side and do the same