My old number was HGGF 40/6. Looking at my original page on the 1939 register on the top line it has E.D. letter code, in my case HGGF. In the 2nd column which is headed Schedule all those at my address have 40. This is not my house number on the road, but a sequential number shown in that column. The next number 6 in my case shows I am the 6th member of my family, parents 1 and 2, brothers and sister 3,4 and 5 and finally me 6, giving me my exclusive number HGGF40/6.