What a gorgeous set! Although popularly called "Nelson Pattern", this set is Chamberlain's Worcester "Japan" pattern 240. Admiral Horatio Lord Nelson ordered a tea and breakfast service in this pattern, and had his armorials and crests added (at an additional charge).
The cup is about 2-1/4" high, and the deep saucer's diameter is about 5-1/4". The set dates c 1802.
Each piece is in excellent condition, with the only flaw being some wear to the gilding (especially on the central flower of the saucer). There are no chips, no cracks, no crazing, and no repairs. Each piece rings when tapped.
The cup is marked with the hand painted pattern number "240". The saucer is not marked.
See Geoffrey A. Godden, "Chamberlain-Worcester Porcelain 1788-1852", London, 1982, p. 109, for a photo of this cup shape, and p. 326 for a description of the pattern number and its cost. The £10,10 noted put it at the high end of the price scale, confirmed by the richness of the decoration as seen here.