Interesting old picture there Norfolktrucker ,were the Birdseye lorries based at GT yarmouth and Lowestoft ?
I found on the internet today where the factories were and what they produced
GT Yarmouth =vegetables ,meat products & composite meals
Grimsby = vegetables & fish
Lowestoft = vegetables ,fish & composite meals
Hull = vegetables & fish
Kirby = meat products,vegetables,fish & composite meals
Eastbourne = confectionary , pastry & pastry products.
Gloucester = Walls ice cream