We won't be going over the school hols (the benefits of having under 4's!) so book away...
re: price, it's one of the cheaper child-friendly farm stays I've come across, and you'd probably be hard pushed to find anything much cheaper with 3 bedrooms during the holidays from what I've seen.
You don't say how old your kids are, but things to do...(Apart from all the stuff on the farm itself)
Beaches within 15-30 mins drive (Saunton/Croyde)
Exmoor Zoo is only a few miles away (use your clubcard vouchers)
The Big Sheep (clubcard vouches again - otherwise it's extortionate to get in!
Lynton & Lynmouth are around 40 mins away - my DS (3) loves riding the clifftop railway
Nice litte aquarium at Ilfracombe, also boat rides and the Tunnels Beaches
Barnstaple Market
National Trust - Arlington Court has lovely grounds that DS enjoyed exploring, they also have the carriage museum there. The house itself has some incredible collections, but skip it if you have small children - unless you fancy an hour of "look, don't touch..look, don't touch...") When we went, DS got told off for touching a display cabinet!
He was being soooo good, and not touching, then got pounced on for touching the cabinet whilst he looked at the things inside
.
Tapely park makes itself sound good for kids, but we were disappointed and thought it was a bit rubbish actually. Nice tearooom though.
There's soft play in Barnstaple (opposite Tesco) if you have horrendous weather and can face it!
Places to eat...we tend to eat in when we're there (morning on the farm, then early lunch or a picnic, then out for the day) but there's the usual places in Barnstaple - Pizza Express etc, The Tarka Inn is pretty nice, The Railway Inn (I think) at Blackmoor Gate does OK food, has a good play area for younger children. Fullams Chinese restaurant is lovely - bit pricey to eat in, but a big discount on takeaways makes the price a bit more average, and it's only a 5-10 min drive back to the house so you can collect & still have it hot. Great Fish & Chips in Braunton.
Hope you can talk DH into it, and if you do, I hope you have a great time!