If i were to build using a new engine , gearbox , axles , suspension , chassis and steering box would it get a new reg as all major parts would be new javascript:icon(''

Yes, also, one major part can be reconditioned (doesn't need to be new), ie. the engine

If the chassis and body are separate parts is the body classed as a major part

Remember you need to keep all your receipts to prove that all parts are new

if you had a receipt from a manafacturer yes, infact there probably more bothered about the mechanicals

Think i would get recon axles and all other major parts new ( selling my house ) do you need receipts for smaller items any advice welcomed

I kept all of my receipts, however small the amount, but I only needed the items listed on the build up form at time of registration.