Yes at 200 metres I confirm a pair of NanoBeam16 configured for 30MHz channel width would be plenty, as long as it is true LOS (not just a small gap though some trees).

In reply to a post by cadmunkey:

I'm quite happy to spend a few thousand getting a reliable connection up and running,

Now there is a dangerous statement. If you are willing to spend money you might like to investigate free space optics like these as an example, but it will be pricey. If you can run a cable, copper (such as cat5e or cat6 cable is going to be pushing it at 200m and may not work as reliably as you may like, but that distance is well in the range of OM3 multimode Fibre cabling, which will be much cheaper than free space optics, and if you get armoured cable more reliable than wireless.

In reply to a post by cadmunkey:

especially if I could sub-let some of the bandwidth to other neighbours for a small fee.

Sharing a connection becomes quite complex quite quickly, and I would consult the services of a solicitor to draw up contracts for usage before even contemplating that sort of endeavour. Technically it is also not easy, and if you set it up you will be the one people come to with problems when things go wrong regardless of whether it is your fault, or even under your control.