I can get over 60Mbps in Hitchin town centre and Welwyn Garden City town centre, but my experience of 800MHz is still woeful.
At a local zoo, in the middle of a forest, and 800 should be rock solid on the map - but like at home, it's very poor and I get 0.5-1.5Mbps max, and often a total suspension of data flow.
3G isn't much better but if I don't force 4G only, it still jumps back and then I have even more spells of no data flow - but if the wind is blowing in the right direction, speeds of up to 5Mbps.
They must have hardly any 800 enabled sites around here, and the coverage maps are incredibly optimistic when they show near blanket coverage for miles upon miles.