Light weight awning required - advice required

Hi, advice needed please.  We have a Bailey Ranger 500/5 and have a Kampa Rally 260 awning.  We find that our caravan rails are too high for the awning.  This means that the awning never gets a tight seal/fix to the ground - it seems to be a bit short and therefore doesn't keep out the elements.  Does anyone have any advice or can anyone recommend another light weight awning for slightly taller caravans?  Thanks