Acer / maple? Id needed - and can I reduce it's height a little?

It's the best picture I could manage. It's quite closely planted there and a bit over grown. If I could.confirm exactly what this is, maybe I could think about 'reducing' it a little.

Thanks in advance

 

The pic isn't clear enough for offering suitable advice unfortunately.
Any Acer can be pruned, but this isn't the ideal time.

What size is it, and what else is around it etc? It certainly doesn't look like a field maple [Acer campestre] which is probably a good thing for you - they become very large trees!
If it's a more desirable garden specimen, and is very crowded, pruning isn't likely to make it more attractive due to that other planting though.

 

It looks like Acer platanoides or norway maple, perhaps crimson king. If it is then they are pretty big trees if given the space to grow and develop. They seem to take a winter haircut well but completely agree with Fairygirl that cutting it will make it harder to keep a natural looking tree.
A picture from further out would help with advice because it does look congested there.

 

The problem with Acers is, if you cut hard at the wrong time they bleed sap. That's why there's this myth that you can only cut them in deep winter. Like any pruning, winter pruning stimulates growth, late summer pruning restricts growth . You can cut back long leaders to two pairs of leaves now, but only if they are not any thicker than a pencil. Larger structural cuts must wait till it's dormant in winter. It could take you 4-5yearss to get it under control.


I will be cutting back the long straggly ends to keep this in shape as soon as the weather allows.

 

It's harder with a norway maple because they are essentially a sycamore, full sized tree. I do agree with everything you said in regards to acer palmatum though. They are very tough though as the world has seen with sycamore gap resprouting.

 

Ash yes I hadn't really taken in the fact that it's a very large leaved variety. When they are that vigorous a cultivar it would be a never ending battle to keep it in check. If it had been kept under control when it was much younger you might stand more chance.