The pianos of Longman & Broderip ae always popular. This example has many good features, but it does offer a couple of 'challenges'.
We do not know the number of the piano, but as well as the familiar 26 Cheapside, it does have the Haymarket address on the nameboard, so we know it must be later than 1782. Not much later, though, I think - as the inlaid garlands and the style of the nameboard do remind me of the '80s pianos of Christopher Ganer (who was one of the makers for L&B). Other details differ from his style, though, so we cannot be certain who was the actual maker.
The ivories appear to be the originals with double scribe-lines, and look good.
All three handstops are present, together with the sliders for dampers (divided) and buff.
The hammers and dampers look good.
The small piece of wood in the crook of the bridge is just a stray piece of mahogany - removed since the pictures were taken!
The 'issues' concern the case, and have no effect on the potential musical quality. The stand is missing; a simple trestle stand would be appropriate. Friends of Square Pianos can provide data to make one; authentic casters and stand-bolts are available from specialist suppliers. The case itself has suffered somewhat, probably from damp, and some of the elaborate inlay-bandings are damaged. These are difficult to repair or match, and the best option could be to replace them with something similar, again from a specialist supplier.
The lid itself has sustained some damage, and the option of a replacement lid could be considered. But at least the case has done its job of protecting the functional parts!
This could be a lovely piano, but it does need a lot of work.