Ghosty, we have had a few Maclaren buggies.
The first one didn't actually break, we took it on holiday and dragged it up and down the beach with bottles of wine and big packs of nappies, oh and DS1 in it until it was decidedly wobbly. We have just kept this one for holidays in the future.
The next one the lie back didn't work properly, one side was difficult to clip back up again, it was very new so the shop gave me a refund.
The next one after that was more successful and like yours lasted till just outside the guarantee, I think it was about 14 months as well. I was running across a road with it and knocked one of the front wheels on a lowered kerb, it only stuck up from the road a centimetre or so. One of the front legs (?) snapped and was hanging off. I took the buggy back to Argos where I purchased it and they were very good and replaced it, saying they were shocked and hadn't see anything like this happen before.
They did not have another Maclaren buggy which I was glad about but the one they replaced it with didn't fit in the car boot (arrrgh)! By this time I had already used it outside and it couldn't be returned. I sold it in the paper and bought a Mothercare Urban Detour three-wheeler, which is great.
All my Maclarens were Mistrals and if my experience is anything to go by I wouldn't but another one. I think it would be worth trying the shop you bought it from as I did not have any problem getting a refund with Argos when my last one broke.
Let us know how you get on.