Tips to improve a nappy pony?

[katymay]

purchased a lovely little Dartmoor Hill pony for my boys, perfect in all ways and a lovely plod along type, but and this is a big BUT, he can be really nappy when he wants, especially when walking along and he decides that really he doesnt want to go any further, he would rather just stand and look at things for about 10 minutes!
He is better out in company but still plods along behind at his own speed and will put the brakes on if he wants to go somewhere different to where we are heading!
he is never nasty, doesnt spin or rear just plants.
both my boys are too novice to work through it and the lovely little 10 year old girl who is riding him cannot get him to move either, a whip doesnt seem to make much difference so she is unable to progress with her riding by trying him in the field.
he is still very young (nearly six) but I dont feel it is a confidence thing as when we trialled him he hacked on his own.
Is there anything I can do in hand to improve this? How can I keep him moving forward if I longrein him?
many thanks as other than this he is perfect

 

[Gloi]

Work him at home in long reins and take a driving whip with you to send him forwards. It shouldn't take him long to realise you mean it and then you can take him out on the lanes in them. He'll soon learn be more responsive to you then if you are walking out with him when the boys are riding him.

 

[Norfolk Pie]

Ditto Gloi -also, and I know this is difficult for little, novice riders, but I'd work on getting him really responsive to the leg - I sped ages making sure people sit in a way that allows the horse to move, and then making sure it goes when asked (should clarify no beatings undertaken!) If the pony isn't responsive to the leg the rest of the time, it might be worth spending a few sessions -even on hacks, with you on foot, addressing that?