mr(s) toffee
jet perf is calculated to allow for eng failures both on the rwy and airborne. crews consider a/c ldg perf before departing, or they nominate a departure alternate eg nzoh. landing distance reqmnts are different in non normal situations.
assym rev thrust is not normally an issue unless rwy is contaminated with snow/ice etc. wellies is wide enough.
and unless you did actually mean west melton, wellington is nzwn