No1 Son is a happy owner of a Beinn 20. He got it at around 5 1/2 and is just about to move up to a 24" wheel Islabike...at which time the Beinn goes to No2 son.
It's a fantastic bike, well sorted (especially the brakes which are special for small hands) and LIIIIIIIGHT
The paint is tough as old boots too. It has been used daily for the school run for 3 years.
I'd thoroughly recommend it. We are on our 5th Islabike now having moved steadily up through the size range. Typically you only lose around £30-50 or so between buying and selling, which makes then cheaper in the long run than Tesco nasties - and your kids will love riding too!
Ride it or milk it!