You raise several issues that should be considered one at a time. First of all, diapers (nappies) with one tape on each side work well for babies with short squat bodies, but don’t provide enough support for older children and adults with longer and thinner body proportions. If your daughter has outgrown the largest size baby diapers, then a two tape per side youth diaper would probably work best. The two tapes provide support at the waist and above the thighs, which help hold it up when wet. I’m not familiar with what’s available in the UK, but what’s sold in most stores here in the US are poor quality for an active incontinent person. The best diapers are Molicare and Abena, which are only available here through online or mail order. Molicare makes a very absorbent diaper called the Molicare Super, which the small size will fit a 50cm waist. If not available locally, you can find them at www.hartmanndirect.co.uk. Another thing to consider is the way your daughter wets. If she dribbles constantly the diaper will last longer because wicking action will spread the wetness to dry parts of the diaper; but if she floods every so often the diaper will probably need to be changed each time she wets. The diaper may contain one flood, but the next one will hit an already wet area and the diaper will leak. For extra support you might try bicycling style shorts made with lycra or other stretchy material worn over the diaper. Some incontinent adults say that the shorts give good support and also help prevent leaks. Finally, cloth diapers are more absorbent than disposables and you might consider using them with plastic pants, at least at night or while at home.