Greater London II (C.S.No. 30) was a 46′ 9" Watson that was built in 1955. There has been no kit produced of this type of lifeboat I’m afraid, or of the previous lifeboats stationed at Southend (Greater London CS No. 3 [1928-41, 1945-55] a 48′ Ramsgate type; J.B. Proudfoot [1941-45] a 45′ Watson; Charlie Medford [1924-28] a 43′ Watson pulling & sailing; William Roberts [1923-24] a 40′ Watson pulling & sailing).
The nearest you can get is a 47′ Watson hull and superstructure moulding from Metcalf Mouldings , however the superstructure is the wrong shape for the earlier Watson that you want. The alternative is to scratchbuild – the plans are still available (from etther the RNLI or the National Maritime Museum – I can’t remember which).
The only kit for a Watson lifeboat is for a 41′ Watson – the Ann Letitia Russell, also from Metcalf Mouldings.
Cheers
Lance