What other options are there on the batting side?
Bring in the only other member of the squad who is a batsman - Jacob Bethell, who however promising he may be, doesn't even have a first-class century.
The only other option I can think of would be to push up Will Jacks into his rightful role as a batsman who can bowl a bit, but I wouldn't want to overdo that (e.g. bat him at 3) just because he did quite well for a while at 8 in the last Test.
So in all honestly the current top 7 is probably the best they have out there, with the possible proviso that Jacks could have earned a place in the top 7, doing anything else is just shuffling the pack in hope rather than a concrete strategy.