Defective couples claim who apparently not a couple?

Referral - Info sketchy but as far as we can tell at this stage is following - :

Client with Bipolar Affective Disorder under CMHT - splits with Partner in May, Partner moves out.

Client had a joint ESA claim She was LCWRA), joint TC’s claim, HB and CTR.

Client claims UC in July as a couple with former Partner who moved out in May, its not clear at this stage why, info limited to Partner wanted to get back together, and client couldn’t face telling Partner relationship was over (we understand Partner had not moved back in).

Claim closed just after the one month mark mid August, because client did not ring up for an initial appointment to verify ID for her etc.

At this stage thinking ahead of the interview we will advise and assist with a new claim a new claim i.e. a single lone parent claim, but looking at ways of salvaging previous UC claim, (struggling because it was a couples claim), and linking claims to maximise income and preserve former LCWRA status from ESA.

Any thoughts??????????????

Further to the above - : Any help with this would be really really appreciated. Including any arguments if we can’t as i suspect link the UC claims back to ESA previous claim to retain LCWRA status!

CMHT signposted client to us - medical evidence suggests Bipolar affective disorder symptoms severe depression with psychotic symptoms, generalised anxiety disorder and agoraphobia. 

Saw client and looked at closed claim journal with her and established date client former partner (not partner at time), submitted claim.

From the date claim submitted one calendar month and 6 days later in order of journal entries claim closed for failure to book an appointment (no mention of MR/Appeal rights), followed by reminders to book interview and verify id online after entry claim closed.

ordinarily i think there is an arguable case for arguing claimant commitment had been accepted on line so that bit satisfied. Then arguing DWP failed to notify client claim defective and allow them time to rectify defect etc i.e. any erstwhile or otherwise reminders were sent out simultaneously as the claim was being closed.

However, i am floundering having trawled through legislation and guidance etc because it was a couples claim as opposed to an award, and in this scenario struggling to make an argument in this instance that a couples claim should be treated as a single person’s claim.

Circumstances of couples claim further to the previous post, in effect humour him and putting off reiterating relationship over, and not booking interview essentially the same reasons.