My word, you collonials have it easy!
300$ for a MIM Strat, in round figures that's £167 - the price of the bottom end Squiers! A typical new UK price is £325. The Noisless PUPS in UK prices are £170 ish per set. Yes, that's more than the US cost of the whole guitar!
We do have shipping and taxes to account for, but that still gets nowhere near explaining the difference. I buy most of my parts from the US and save oodles of cash.
I've an 04 US Strat (UK Sourced) that I've fitted locking tuners
and vintage noiseless pups (US sourced) to at at a total cost of £730.19, that's about $1134 US.