Clothing for tall ladies

Hugh street shopping is always a depressing experience for me. Not only are my feet too big for anything other than the bloke's section but dresses are always always always three inches too short.

Assuming I need to shop online, boohoo's currently tall range is lacking and it's been ages since I've shopped properly. Looking for nice holiday dresses for my trip to Spain in the summer. I wear a UK 18 and my legs aren't something I'm overly happy to show in abundance.

Grateful for any suggestions!! Thanks in advance xx