But getting back to the price of hardware it is frustrating to see Davis kit on sale over there for $150 and costs £150 over here. I wish someone would explain why it has to be like this.
There are several reasons, as you might imagine - much smaller individual country markets than the US, shipping from California genuinely is a non-trivial cost, import duties (ie separate from sales tax), the cost of providing local support (it's effectively provided by the Davis factory in the US, whereas it has to be self-financing in export territories) etc.
But the main reason is that Davis, along with many small US companies it has to be said, are relatively timid about doing business overseas and insist on supplying only via a monopoly trade distributor in each country rather than being prepared to supply individual dealers direct. Retailers have no choice but to buy through their local distributor, which has two consequences: First, both dealer and distributor must each make their own margin to survive as a business. Second, the sole-rights distributor has no competition and hence can charge whatever they think the market will bear. There's plenty of competition at the retailer level, none of whom are making much margin at all. But essentially none at distributor level. The only way things will ever change is if Davis are lobbied to persuade them to supply (larger) overseas dealers direct.