Spot on @Aethelred The moneyer Iohan at Canterbury and the hair as two crescents with pellets is a telltale indication of class 5. I think the full class would be 5b2* because of the round top of the letter R in the oversee legend and the scepter dividing RE/X between the E and X. Its a very nice penny of John.
Thank you @TheRed I have a hard time with these and some of the Edward Pennies, but getting this right is a good sign that I'm making progress (or got lucky). When I bought it, it was in a holder attributed to Henry III.
You're welcome. Thankfully your coin had the reverse legend largely intact and the bust was well struck. The short-cross pennies can be so aggravating some times. If it wasn't for the fact that they cover three of the most interesting kings of England I would probably pay a lot less attention to them. Edward I-II pennies can be an even worse case due to the lack of moneyer. If you don't have it yet, I would highly recommend The Galata Guide to the Pennies of Edward I and II. It is a great guide to the different classes and fairly inexpensive.
As far as English Hammered references, all I have are Spink and the North books, so I'll have to find that one. I consider the era from Henry II to Henry III the most interesting in English history and I'm especially fond of Richard and John.