Ashbury are a UK firm who sell a wide range of instruments including a range of ukuleles. Their ukuleles are fairly inexpensive (but not the very cheapest) and very similar to other ukuleles out there (such as Oscar Schmidt). The range includes a resonator ukulele very similar to the Johnson resonator.
I have an Ashbury Koa Concert ukulele and it's my favourite day to day ukulele and I play it far more than my other ukuleles. It's very easy to play, the action is low and the fretboard smooth. It was my first 'proper' ukulele and I don't think I could have made a better choice for a starter uke.
It should be pointed out that the koa wood is just a laminate - it's not solid koa wood - and you wouldn't expect it to be at this price.
Me playing my Ashbury Koa Concert Ukulele.
On eBay UK
Ashbury Concert Ukulele