dh has just come downstairs with more suggestions as it's his home town...
Instow beach is also a nice sandy beach, he said 'warn them about the traffic through barnstaple' if you're heading towards ilfracombe from bideford... just be aware that the journey can be a bit of a nighmare with a fair few stop and starts... (an hours journey if traffic not too bad!)
Northam Burrows has a lovely pebble ridge - if feeling adventurous with kiddies),
instow beach is great for a beach but watch the tide,
westward Ho! beach is a bit wavy too!
(Dh is coming out with ideas and suggestions fast and furious now!)
Hartland Quay has magnificent views of the cliffs, you can get to the beach and rock pools at low tide, with a good pub friendly to kiddies (i.e. it's got highchairs!!) - you have to pay about a £1 to reach the quay... but the views are spectacular
Northam Pool has lots to offer with kiddies pool if in need to escape the rainy weather
Braunton Burrows - if you're into nature, lots of flora and fauna
Rosemoor Gardens just south of Torrington is a nice place, good cafe and pleasant walks (the gardens are massive) RHS so you have to pay to go in!
If you are into walks the walk from Westward Ho along the coast path (heading west) is lovely on a sunny eveing (if you can get a baby sitter!)
The Tarka Trail - you can hire bikes and cycle to the Puffing Billy (pub, standard pub fare and kiddie friendly) Bideford heading towards torrington.
hope this helps....!!!