bearded dragon not growing :(

i have a little beardie who is 1 year old, he was originally kept in a tiny 1ft tank with another bearded dragon after being attacked and the shop unable to care for him i took him in. that was in February since then he has only grown in weight not much in length. he is about 25cm long he was 18cm when i took him home last year. he is in a 4ft viv with a 10% uvb tube just under the length of the viv, his basking spot is 113 and cool side 86. he has a mix of crickets, roaches, silkworms and mario worms all dusted everyday as well as greens (spring green, rocket, butter-squash etc) he has baths 3/4 times a week, poops regularly and sheds regularly.
i see majority of dragons his age double the size of him, i have had fecal tests done and they came back clear. he seems healthy in every other way just wondering if there is anything i can do to encourage growth?

He probably has stunted growth in general from the situation he was in. Perhaps the food has been utilized by the beardies to get him back up to a healthy weight so he can then start putting on length. If he is eating pooping and the vet says he's alright, and he's acting like a normal dragon he's probably fine. Either way he sounds like he's better off now. How old was he when you got him?