Hi,
I will stick my head above the parapet with the expectation of being shot down very quickly.
I don’t think the rules on this are any different from a Pensioner claim to a Working Age claimant who requested backdated HB for 52 weeks, the general rule is that we request an ROD from the RO within 3 days and the claim being made and the decision is valid for 52 weeks from the referral date (unless they have a change of circs that affect the ROD).
In your case the RO would not provide another decision as the decision he has supplied already restricts the rent to less than it was before the rent increase. I expect the restriction by the RO is either for Size or Significantly high and as it is valid for 52 weeks as there has been no change that would affect the his valuation.
If you change the thinking slightly and assume he had claimed prior to his rent increase in 2005, if you had referred and received your ROD with the LRR of £368.33, you would not have been able to refer increased rent of £500.00 due to the restriction already in place.
With regard to the £368.33 provided by the RO I imagine they are trying to be helpful and have provided the LRR for the property type in the area for July 2005.
Hope this helps or that Peter Barker or Kevin D can come along and provide you wih the regs etc you need.
James