Holiday Whilst Caiming ESA

Hi there, my husband is on contribution based ESA and now that I am retired, I want to spend most of the summer abroad (within the EU). We contacted the DWP in March 2015 and asked how this would affect his benefit and they told us that there was a maximum 26 week limit and he had to write in to confirm the date of departure - which we did - and subsequently the date of return. After we notified DWP of our return, my husband received a letter from DWP telling him that he was only entitled to FOUR weeks benefit and that he would have to repay the rest! DWP also closed down his ESA claim and started up a new one, which meant that he lost the transitional ''top up'' payment which he had been getting following his migrations from IB to E&SA. We requested a mandatory reconsideration and DWP have now cancelled their demand for repayment on the basis that my husband did nothing wrong, but they still insist that their decision is correct.
I have read the Regulations and they are really ambiguous. There is a four week limit on ESA,in general, but there is a separate paragraph specific to contribution based ESA which states that this particular benefit will continue to be paid during a temporary absence from the UK (with no definition of ''temporary''). DWP seem to be saying that the general four week limit carries through to this paragraph which is specific to contribution based E&SA, but I don't agree. In any event, these Regulations are at best undeniably ambiguous and, by the principle of contra proferentum, the interpretation must surely favour the claimant.
I am also wondering whether there is some EU Directive or Ruling that applies here as surely a contribution based benefit should be exportable within the EU?
I would be really grateful if anyone out there has any information, opinions or comments which might help as we really need to know where we stand for the future.