The cordless phone (with last call facility) was faulty and sent back to the manufacturer two days before. Have asked before, but no-one seems to know/have responded as to who found the fault or returned the phone.
Likewise, its return. Can't find any documentation as to the nature of the eventual repair.
This was given as the reason the bedroom phone was bought downstairs. A fortunate coincidence for whoever did the shooting upstairs.
Presumably, the phone hidden under clutter was either faulty or forgotten.
Re blood spatter etc
If Sheila is the killer, we have to accept the 'washing' theory, then wonder about the evidence in respect of the shower/bath, towels, clothes etc.
We all accept that blood analysis is radically different now - in the UK specialist courses weren't on offer until 1988 - but I guesstimate that the initial 'suicide/murder' interpretation resulted in less analysis being undertaken than was the norm for 'murder' back then.