I personally think that the "Where's The Path" mapping site knocks the spots of Ordnance Survey Get a Map.
The Get a Map "map window" is very small, and the zooming and panning operations are abysmal in comparison.
With the WTP site, the default view shows Ordnance Survey and Satellite views in two adjacent windows, and if the user selects linked panning and zooming, it is simplicity in itself to find the exact spot you are looking for. - The fact that both map and satellite view can be seen simultaneously is a great aid.
There are several options for the desired grid reference, with up to up to 1 metre square level of accuracy.
eg. the user can select 4 figure, 5 figure, compact 4 or 5 figure - (i.e with no spaces so they may be copied directly to recording software), lat.long., Vice County, etc. etc., and the exact grid reference is automatically displayed wherever the mouse pointer is located.
It is also possible to add user defined routes on these maps, with options for giving both route lengths and amount of ascent over a given route.
There is also the facility for entering a known grid reference to immediately bring up both map and satellite views centred on that reference. (Or any other valid address/location).
Regards,
Mike.