cutting a hedge

You say you can't find a trimmer - I am only guessing what you've tried - secateurs, shears, powered hedge trimmers? I suggest that you go and hire a heavy-duty petrol hedge trimmer. You can hire them for a day at a reasonable cost. That's what my husband has - as we have tall hedges, he bought one.That should cut through anything.

I guess also - only a stab in the dark - that the hedge might be Lonicera nitida, if the leaves are small and box-like and the hedge is springy? This needs to be trimmed twice in the summer (early and late) - but avoid bird nesting times!

Why can't you approach your neighbour?
If it becomes too much of a problem, contact your local Council for help under the Anti Social Behavior Act 2003 section 8 High Hedges. This was bought in because of the dreaded leylandii, but it covers all evergreen hedges. You could ask their advice if you don't want to get them too involved. If you are going to tackle it yourself, I agree with Spritz, cut the hedge down with a heavy duty petrol trimmer, and legally you are supposed to return all cuttings to the owner of the hedge, but if you don't get on with your neighbour that probably wouldn't be welcome. You could write them a letter outlining your concerns. Take a look at some of the comments I have made on leylandii hedges, they might be helpful

i have tried to cut this hedge back but because the inside of the hedge appears to be dead the result is holes appear even though i am only cutting back to my border