Looking at trailers for the kid – has anyone had experience of the B’Twin Child Bike Tow Trailer?

http://www.decathlon.co.uk/btwin-child-bike-tow-trailer-yellow-grey-id_8209834.html

We have a near identical on bought from eBay for about £70. Turns out actually to be Lidl branded. It came shipped from Germany.

No suspension, basic seat, but cheaper trailers will always be a compromise compared to chariots etc. A few custom mods will improve it no end.

Ours has lasted years and covered serious trails.

Halfords go a double trailer .. Currently in the sale. Not sure how it differed from the Btwin but I have the single one and its plenty good enough (assuming you are not doing any crazy off road stuff).
10% off with BC membership too

http://www.halfords.com/cycling/accessories/child-bike-seats-trailers/halfords-double-buggy-child-bike-trailer