It's difficult because his average is appalling so he shouldn't be in the side if you look at that in isolation. But I don't think there are obvious candidates to replace him and I would expect, as always, there's a view to the Ashes here. His average against Australia is very good, on the extra pace and extra bounce in Australia he's likely to be more comfortable given his height. It will be Ashes or bust for him, and a few others I'm sure.
Ahmed is having a very good season but it's Division 2 and early days. With his ability to bowl as well, it wouldn't be a surprise if he's considered. Tom Haines is another candidate but Bethell is the one they'll be most keen to integrate into the squad. He looks a superb talent. Thrown in the deep end and performed excellently in NZ. Took some wickets too! Averaging 52 with the bat and 26 with the ball in his young test career. He's got a bowling average under his batting average in all three international formats at the moment.