UC versus HB in full service area

Claimed IS from 20.4.2017 but did not claim HB until 11.5.2017.

As they were in a Full Service area from 10/5/17, the claimant was advised to claim UC: they did so, and so the IS claim was closed and HB was no longer possible.

Question – what about the period between the beginning of the IS claim and the beginning of the UC claim?

Is possible to complete HB claim initiated before full service commenced. As long as claim or enquiry re HB submitted to DWP through CMS process before full service started. Could have done so in first place without claiming UC at all, but what’s done is done so HB now can only run up to UC claim date

Thanks, that confirms what I had thought (Honest!)