I'm very excited to hear of your plans for another Sharpe book, especially with the idea of setting it just after Waterloo.
As someone has already commented I would love for Sharpe and Fredrikson to reconnect (and possibly patch up their differences). I also wonder if Captain Charles Morris might make an appearance. Considering he was a officer of the 33rd foot's light division in India and that the 33rd foot were at Waterloo. Maybe he was recalled from the garrison of Dublin Castle?
Whatever you decide to do with another Sharpe book, if you decide to do it (but you know you want to, go on Bernard please!) I look forward to reading it.
All the best
I look forward to writing it and, yes, I think Morris needs to be there.