We have real difficulty with buying clothes for our children. The fundamental problem seems to be that the assumption made by the designers is that children who are as long as ours will be substantially wider. So we have ended up buying quite a number of clothes (bottoms) which just don't support themselves. An adjustable waistband makes a lot of difference. A fair number of garments have what looks like a means of tying and tightening the front - but it turns out on closer inspection to simply be trim, which only tightens a 1cm section at the front!
Another problem is that even well-established shops who one would hope ought to know better insist on offering clothes for pre-teens that make them look like tarts. (Is it just me that finds the marketing of Playboy stuff at anybody under 18 really offensive, by the way?)
"Pumpkin Patch" are new to us. We happened across them in Crawley, and discovered that the clothes they were selling were not only age appropriate, but they also seemed to fit and adjust better than many of the other more established shops. So well done them!