I have a small book called Coastal Ships, By D.Ridley Chesterton, Published by, Ian Allan of London. I obtained the book in 1966 so it will out of date by now. London and Rochester Trading Co Ltd are on pages 52 and 159. In addition to the ones above you can add,
Elation, built 1963, 212 gross tons, 99 ft long and 22 ft wide and engines aft.
Function, built 1963, 210 gross tons, 99 ft long, 22 ft wide and engines aft.
Under two 200tons you have the following.
Silver and many others
They also had Tugs,
Dragette, built 1947 or 50 tons and 300 brake or shaft horse power
Also had small tugs like the Goaxette, Nudgette,Shovette and Snatchette