I think a huge part of the cost is whether you have a whole donor car or just buy parts.
Here you could get a 3sge, box and shafts for less than $600 (~200 pounds), whereas it could be double that for 3sgte, box and shafts. Plus the need to have an SC outer shaft already.
How much did your swap cost roughly aw11man (may have forgotten if you've posted the cost on clubaw.co.nz)?