green fingerd people or tree doctors

[londonladliam]

hey all,

after some garden advice,thought we all play out doors with our toys so might be a place to get some help.

basically i want to cut the top of the tree off(the left side of the hedge) to make it level with the other one to the right but,this will leave a a very thin top part of the tree as the bottom of it is also very bare.

is there any way of increasing growth of new branches in the lower half of the tree. sounds silly but, can you cut green ones the upper part of the tree, drill a hole and plug it in and hopefully it grows?

pics bellow

any help welcomed

liam