London, Birmingham, Bristol, Cardiff, Edinburgh, Glasgow, Hull, Leeds, Liverpool, Manchester and Salford, Newcastle and Gateshead, Nottingham and Sheffield. The Ordnance Survey drew town plans for many more places; these are the ones in the register so far, each sheet checked for a licence that lets its print be sold, and more are added a city at a time. If your postcode falls outside them the search says so rather than moving you somewhere near.

If it was standing when the surveyors came through, yes, and drawn in its own outline. If it was built later you will find the field, the orchard, the brickworks or the terrace that stood there instead, which is often the more interesting print.

Because they digitised the sheets and publish them under a licence that permits this, on the condition that they are credited. That credit is printed on every one of these, in small type under the map. It is not a watermark and it is not negotiable — it is the reason the print can exist at all.

Yes, though it opens as drawn: the sheet exactly as it was printed, with your palette setting the paper around it. Switch on "Colour the survey" and the engraving is carried into two colours from the palette, its ink and its paper, so every line and letter stays where the surveyor put it and only the colours change. A dark palette turns the sheet pale on charcoal, and with only two colours left a century of foxing falls away, so a coloured print often reads more clearly than the scan. The credit then says the map was recoloured, because the licence asks that a change be shown.

As much or as little as you frame. Two hundred metres across gives you your own street and the ones behind it, with the lettering large and legible; four hundred takes in the park, the station and the school. The studio tells you how sharp the print will be as you change it, because a wider frame spreads the same engraving over more paper, and it offers only the sizes that frame will print sharply at, up to A2.