Most unlikely.
It will be for the magistrates to decide whether or not to grant an adjournment, but generally Courts expect all parties to be ready to proceed. The Bench will most probably take the view that this issue should have been identified and solved some time ago.
Most solicitors would adopt the same line as your husband�s. In addition, most Benches will not permit a represented defendant to address the court (except when giving their own evidence in their defence). This is as much for the defendant�s benefit as anything else, as they could compromise the defence case if they say something they should not.
Best find another solicitor pronto, but of course he may find the same problem occurs.
Just out of interest, did this alleged offence occur on private land that was also not a �public place� for the purposes of the Road Traffic Act. If so, why was he charged?