Canada is a Commonwealth country man,  I think it would very hard to block you.  Contact the nearest British Consulate and ask.
You should contact them anyway to make sure all your ducks are in a row so to speak...
Or, Josh could logically surmise that Junior is talking out his ass as per usual. 
Following this thread, I have the distinct feeling of déjà vu. 
To my way of thinking, if Josh takes the trek to Britain next spring, he is the winner in this farce. He gets a vacation and Junior gets nothing but destroyed. 
- Disclaimer; I don't dislike Junior, I am just bored with his predictable antics. 
I find it hard to believe that grown, intelligent men engage in such nonsense as this.