My parents will be celebrating their diamond wedding anniversary and I am looking for a suitable venue. They live near leicester (uk) so anywhere within an hour or so drive would be ok.
The hotel would be ideally:-
Privately owned
Serving local unpretentious food
Not too Large
Having a small private dining room
I am really looking for a word-of-mouth recommendation from someone who has attended a really good function somewhere suitable.
Many thanks

I can't quite hit all the points you mention, but have a look at -

http://www.theolivebranchpub.com/
(it is a very nice pub with a separate house for accommodation -an award winning venue)
or
http://www.hambletonhall.com/
(small pricey award winning hotel)

Thank you so much for your input - Hambleton Hall I do know but thought that my parents would find it a bit intimidating. I love the Olive Branch which I hadn't heard of. The idea of a pub with rooms hadn't occurred to me but it is a really great idea.

Just remembered another one that may be suitable -

http://www.horseandtrumpet.co.uk/home.htm

I think it would be highly convenient if you chose a hotel in the close proximity to an airport. This will facilitate easy conveyance.

http://www.east-midlands-airport.co.uk/hotels/

This website lists quite a few hotels that match your criteria. Check them out.
Cheers!