Richard - sorry i think it was Aldi not Lidl. Just checked their website but nothing in offers. Sure I wasn't dreaming though - perhaps tonight it'll be Orange Sub3 for £99.99 aaaahhhhhhhh!
I got a child trailer from Lidl last year for £60 - proper job it is too. Exactly the same as the ones you see for £200+ (I compared them closely)
Steel folding frame frame, nylon webbing seating compartment with plastic base and full harnesses, fully bearinged quick release wheels (steel rims tho') full front and mesh flaps. Fully flexible joint. lights, flag.
Fantastic deal. Children love it. I'm sure you could also use it as a kit trailer.
I have a YAK myself. I think it's great on roads and good tracks (i.e. bothy runs with a load of whisky & firewood), but when the going gets tough the trailer can be a liability. It's also a pain if you're having to negotiate obstacles in crowded streets, especially when reversing the bike (hopeless). On balance, I prefer panniers for long distance touring on roads of bad or uncertain quality.
Those Lidl kids trailers are brilliant for the money and they are stable with the sprog in even tanking down hills on a tandem they are so cheap they wont be worth much second hand so I intend using mine as a kit trailer when the sprog is to big