I called V and apologised on Mum's behalf and gave her my home number in case she ever needed to contact me. I was midway through offering to pay the monthly charge to have Mum's phone number blocked when I realised that there was an easier way to deal with this. I rang Mum and asked her to find V's number.
"Yes, I'm expecting her now... I don't know where she's got to."
"Mum, what day does V come to you?"
"Oh...er... she comes on a Wednesday."
"And what day is it today?"
"It's.... er.... I think it's Tuesday?"
"Mum, go and look at the clock I bought you."
After we'd established what day it was and found V's number in Mum's address book, I asked Mum to scribble over the number until it was illegible. I then explained why we had done that. Mum admitted that she called V often. I told her about the early morning calls, which she tried to deny. Oddly, she seemed more upset about the calls at 6am than the one at 3. I made several attempts to explain that 3am was even worse than 6 though I'm not sure if Mum took this onboard.
I remember a TV drama about Alzheimer's back in the 80s, where an old lady took to vacuuming her lawn in the early hours of the morning. Thankfully, Mum isn't likely to do any housework or gardening, but it seems that she's capable of making the night-for-day mistake. Looking at the phone bill I posted on here a few days ago, I can see that some of the directory enquiry calls were in the early hours. It seems we've reached another milestone in Mum's decline.