Can anyone suggest where to see 2 specific type of owls around Cambridge?

I know if anyone won't respond, but can anyone perhaps suggest some sites near Cambridge where I can watch long-eared and little owls to complete my collection?

If people think I want to collect eggs or will disturb them, I can email an entire mountain of pictures of shy birds including an oriole which I did not disturb. I have observed the peregrines at the chalk pits for weeks and know of tawny owl and sparrowhawk SPECIFIC nest locations. 

I have observed:

Long-eared owls in Russia without disturbing them

An eagle-owl without disturbing it

A snowy owl

I have seen and photographed barn owls for long periods

I have observed and photographed lots of short-eared owls

4 tawny owlets

I can prove any by the snowy owl with images as well. I can post all of them if someone asks. 

My point is, if someone can PM me the location of a long-eared owl roost near Cambridge, even a vague idea, I would be extremely grateful. If you live near Cambridge I could offer the sparrowhawk location in return, or a lot more. 

My main question, however, is LITTLE owls. 

I visited the Wicken fen logpile twice and not once did I see it! Besides that is a bit far away. If anyone can suggest anything, do pm me. I would be supremely grateful. 

Thank you!