I got a comment about this tree from a reader in 2013 that said this tree needs more branches and growth. He was right:-
Since then I have fed very heavily and also had a go with a number of approach grafts and thread grafts. The approach grafts all failed but the thread grafts appear to have taken. I have not yet cut the parent shoot away as I intend to leave them attached until next spring. My limited experience of birch is that even though the graft appears to have calloused over it does not easily merge with the receiving branch cambium and may not really have taken. Time will tell. I have left the graft branches untrimmed to build up thickness.
The pics show the overall extension growth this year before and after a trim. The extension growth has been trimmed to produce some backbudding and ramification. The tree will need trimmed and branches placed etc during the dormant season.