We have outgrown our buggy and although the local health visitors/children's centre/charities I contacted didn't want it, one of them pointed me in the direction of Storehouse at Riverside Vineyard Church in Feltham. They receive referrals from healthcare professionals and provide clothes and equipment for children aged 0-11 whose parents are in need.
Just in case anyone else is looking for a good home for their old baby equipment, their contact details are: 020 8890 2626/[email protected]. Or you could offer it to FARA or Humanitas, these would have been my next ports of call.