I believe that Brakes on all the series landies were an optional extra, and then quite unique in the motoring word. They are Proportional Brakes.
1 They work in direct proportion to the amount of fear involved , and
2 They fail in an inverse proportion to the Gravity of the situation.
PS. The most common cause of bad brakes is the leading / trailing shoe issue. Most shops get them either wrong or they get 2 leading and 2 trailing together which doesn't work too well. Also the power bleeding or lifting the front is a must.