Hi Gareth,
Your wife just needs to write to DWP, declare a 'change of circumstances' and ask for reassessment. This will trigger a complete reassessment, including ESA50 and possibly a face2face assessment.
In this situation the onus is completely on the claimant to prove that the condition has worsened since the last decision and that the Support Group criteria are now met.
Don't forget that the ESA mobilisation descriptor doesn't just look at walking. If your wife is considered to be able to self-propel her wheelchair for 200m or more, she will not score any points for that descriptor!
Qualifying for the Support Group If you have any further questions about the process, please reply to this message and we will do our best to help.