Amazon have a half off offer on the Hedstrom 2 in 1 Swing, selling for £25 instead of £49.99. This two in one swing should have a good lot of life in it as it converts from baby to toddler.
The highly versatile Hedstrom 2in1 swing easily converts from a toddler swing to a junior swing (baby to toddler, same difference, different child). It comes with a high back, chunky seat and a 5-point safety harness for extra comfort and safety.
The junior seat has adjustable ropes and the whole thing has a powder-coated steel extendable frame. It is apparently also very easy to assemble. It comes with ground pegs for extra stability, an allan key for assembly, and a screw pack and instruction sheet to help you with construction. Assembled size is H182cm W180cm x D154cm.
The age recommendations for this set is from 6 months to 10 years - although I don't know that it's guaranteed for that long .
Thanks to wishihadadonkey at HUKD