What type of hedge do I have?

I have recently moved into a new property and there is a hedge that I am not sure what it is and hence the best way to maintain it.

It is also a little thin at lower level so not sure how to force the hedge to thick/grow out lower down.

 

Generally to thicken the hedge up lower down you need to allow light to get to it so you need to cut it so the top slopes slightly inwards so the top is thinner than the bottom and the light can get down to the bottom

https://www.rhs.org.uk/advice/profile?PID=398

dont know what kind of hedge it is tho sorry im not up on my hedging plants

 

I was about to say hawthorn too, @JWK .

If so, careful when you cut it, and clear away any of the trimmings that fall, as there will be 1/2" long thorns in there, all trying to get you!!

 

Possibly hawthorn, but looks more like field maple to me. Has it got thorns?

 

Acer campestre...common name field maple.

http://upload.wikimedia.org/wikipedia/commons/6/66/Acer_campestre_005.jpg

http://en.wikipedia.org/wiki/Acer_campestre