1. Unfortunately, got a stone chip in the windscreen today (less than 2p-coin-sized on the passenger side). Very much hoping that it's repairable. If not, how easy is it going to be to get hold of a replacement windscreen? My insurance only covers me up to 1000GBP but I'm guessing Nationwide Windscreens (my insurer's preferred repairer) might have trouble getting hold of a replacement, so worried that the total may go north of 1000.
Worth getting it checked the windscreen from FB posts are around 100-200 pounds.
2. The vehicle only came with one key (private sale). I've found a company - autolockmaster - in Cheltenham who say they can cut me a spare and programme the chip for about 160GBP. Does anyone have experience of this company and is this a reasonable price? Are there other alternatives out there?
Buy a key off the internet or go to Toyota directly that way you wont face any issues. As the coding for these keys are different from the UK.
3. Is it worth getting the vehicle 'waxoiled' underneath? I've heard Alphards are less prone to rust issues than Mazda Bongos, say.
YES - had mine done as Japan does not salt their roads it does not rot, but here it can rot quickly. so get it undersealed.