Kindly Mexican friends have supplied many (another one's bringing a big batch back next month hopefully) but I've purchased a kilo off MexGrocer (co.uk) that were decent and keenly priced (<£25), albeit fairly short dated. They're one of the few able to supply meco chipotle rather than the cheaper moritas -tbh you rarely even see moritas in Mexico, with the vast majority dedicated for export. Moritas will cost you about a fiver a kilo less. It's very much worth the upgrade fwiw - they're far more rounded and fuller of flavour. I can give you a great supplier off all kinds of dried mexican chillies (on ebay) - great quality and fresh, but a little costly. Thoroughly trustworthy and knowledgeable bloke too - highly recommended.