[Oscar the dog]

Any one any experience of which is best to grow for the berries, and if produce in first year etc

Did the usual google search but got a bit baffled.

[Yorkie]

Can't see any previous posts on here about it, and this is probably the most useful of the RHS results:
http://apps.rhs.org.uk/plantselector/plant?plantid=1073

It's not clear how you think you might grow them - if from seed then I'd expect it to take several years at the very least before it's big enough to think about propagating itself (i.e. getting to seed).

If taking cuttings, again I'd expect it to take a year or few.

If buying a bush, then it shouldn't take too long to reach fruiting stage depending on how big it is.

But I've never grown them so am making this reply up as I go along! 

[solway cropper]

Juniper is very hard to grow from seed and is best propagated from cuttings but as it is a slow growing shrub, even this method can take 3/4 years to get something big enough to plant out and many more before berries are produced. The Forestry Commission have some info but it is quite technical.