Jill. wrote:

Slow on dialup

Erk - forgot people still had dialup If you have dialup, you're still
better off looking at other sites with OS maps on - I decided to do this
because I like the flexibility that Google Maps gives you and it makes
it easy for my to write my own code on top of the map.

Could you get to the area by postcode first and then refine from there?
Height was correct

Sadly not. Postcode data is protected by copyright and I am not in a
position to pay the extortionate fees that the Royal Mail want. I have
my eyes on a public domain product produced by the US government which
contains latitude/longitude data for something like 4 million locations
worldwide - I might build that in to make it quicker to find where you are!

Jonathan