ID of a mouse please

Our cute little visitor was happily grooming itself this afternoon in the sun, and returned to take some bread. It was perhaps half the size of a common house mouse, but similar in colour, greyish brown rather than orange. The tail was shorter than usual mouse tail but we can't find any vole to fit the look.

So, very small (body around 3cm), greyish brown, shortish tail, diurnal, tame. I'm banking on harvest mouse apart from the colour, the Teenager says it's a house mouse pup.

Any ideas anyone?

Sorry, no photos as we were too busy watching it

 

Hard without a pic @Selleri
House mouse or field mouse? Types of mice

 

How about a (young?) field vole?

 

Thanks @Upsydaisy for the link, and @Scrungee for the pic. I'm starting to bend on the vole side rather than a mouse. The size is puzzling though, it was indeed very small, I mistook it as a snail when it was cleaning it's nether regions and curled. Probably a young of something.

 

Gosh !! It was small then!

 

A baby something, and judging by the fact that it was so fearless and enjoying the sun in an open position, probably ill with something. Small animals like that are in general not very tame in an exposed area. Anyways, it took away a chunk of ciabatta bread nearly the size of it's head and looked happy. I hope it will come back

 

Have your camera ready !!!