Hi Stuart
The bike is 6T Thunderbird. The book is the workshop Instruction Manual covering models from 1945 - 1955. I don’t think they did one for 1956 as new models were introduced for 1957. The current tyres, I shall be changing the rear very soon, are Avon front, Dunlop rear. Whether the reduction in pressure helped as much as I feel it did is open for discussion but I am satisfied today’s ride was far better than Saturday’s.