So, here's the next part of the puzzle!
On Monday, I programmed a scheduled charge for 11pm on Wednesday until 9am on Thursday and then at 12.30am on Friday until 9am on Friday.
On Wednesday, when I finished for the day and went to plug my car in, my wallbox was showing a solid green light and my timed charge worked.
I've just went out to have a look at my wallbox and it was showing a flashing green light (indicates the car or wallbox has stopped charging). I've swapped cars to charge up the battery on the other car and when I unplugged the first cable, the wallbox light turned blue (stand-by).
I plugged in the next car and it immediately started charging, so I unplugged it.
My app confirms my next scheduled charge is 12.30am tomorrow morning so I've put in another scheduled charge starting at 11pm tonight, until 12.15am (it wouldn't let me go any longer) and watched the wallbox as it changed to a flashing blue light (it's updating itself) for 5 mins.
The wallbox light has then turned solid green and I plugged in the car and it shows as connected but not charging.
From this, I think I can confirm - if your wallbox has a solid green light, your next scheduled charge will work. Also, if you change your schedule, it will take 5 mins for the wallbox to update itself and I'm not sure why, but my charger doesn't like starting a charge at 12.15 or 12.30am!
I'll leave my 2 scheduled times to see if the app goes from 1 charge to the next and on my next charge, I'll try it at 12.45am and see if it likes that any better!
Cheers
Bloggsy