you could try a corner bath where you've put the shower currently, and the basin farther along the long wall. A corner bath makes for an expansive deep shower tray...
https://www.victorianplumbing.co.uk/laguna-corner-shower-bath-with-screen-panel?campaign=googlebase&pagetype=shopping&gclid=Cj0KCQjw1ZeUBhDyARIsAOzAqQLkYDnw4MHtv6EZ_RwTgQxbrzF5g0GE7yzSuxCatyBufDe6j6DLTCsaAtW1EALw_wcB&gclsrc=aw.ds