Both are beautiful boards but for a £500 - £600 build it might be a bit pricey?
Well the CPU+mb is half /just over half your budget, ram for £50, GPU ~£150(or less I'd you go the b grade route). Leaves case + HDD(do you have a HDD you can reuse?).
Would most like be in the £600-£700 range rather than £500-£600.