The Hamax Siesta On Frame Children's bike seat allows you to safely take a child from 9 months to 4 years. You can tilt the seat. A child's seat with multiple comfort options.
Designed for children aged 9 months to 4-5 years, under 22 kg.
Designed for 28-40 mm tubes using a frame attachment mechanism.
Can be tilted to 20°; adjustable foot rests; space for helmet, etc.
Guarantee : 2 Years
Cheapest rival I could find was Halfords @ £68, so even with delivery you'll save yourself £17. The RRP on this seat is around the £100 mark, but its on sale with most online retailers. Gets good reviews too.
If you spend £70 at Decathlon you get free delivery, or you can check your local store and pick it up for free !