ESA Abroad - more than 4 weeks but not permanent

I would appreciate any advice and guidance on this query as I appear to be getting nowhere.

Facts
>British claimant
>Previously in receipt of IB circa 20 yrs
>Converted to ESA (contribution based) recently
>In past under IB was able to be temporarily absent and travel to see relatives in another EEA Country for upto 26 weeks
>Now under ESA Regs 151 - 155 there is limitation of 4 weeks

Aim
Client wants to travel for in excess of 4 weeks without having to export benefit

Summary
Having examined the guidelines it would appear my client would breach ESA regs if exceeding 4 weeks.
However, if client wanted to permanently move this would available via Co-ordination of EU Benefits.
Problem is my client wants same rules as before.

ESA DMG
I have scoured the net for the ESA DMG on this point and come to a blank.
I want to find out if any transitional protections exist for him to rely on IB rules or whether there any solutions.

Any guidance, tips, advice extremely welcome

M