My yard is in Kingweston, typical farm....no school though only fields but I love it! There is a new big DIY yard in Somerton too...I saw an advert in the summer but can't remember the name sorry!
Naydon Equestrian is in Lydford not Somerton. It is nice there but they have recently only changed to part livery....before they were £30 a week DIY....so thinking part livery more expensive! http://www.naydonequestrian.co.uk/
My livery is Home Farm in Kingweston, as I said very limited facilities as very farmy but lovely place. There is also the Divoky club in Butleigh but if you want your pony near then they are about a 15 minute drive.
For Kingweston I would say the yards in Somerton are your best bet...literally like a 5 minute drive! Unless you can find someone with a few stables and land...there are always little yards dotted around with a few privately owned horses I see in Kingweston that I am sure if you asked then they can offer livery!