Hey Rachael. Can't agree enough about the book "HSH, HC" - it is also my bible and a book that I've spoken about quite a few times in your thread, I think without actually posting the title! I do think he is a little harsh in some respects, I have to say, but I'm all for taking it all in and just finding a healthy balance. He's very pro what he calls the "extinction method", ie to basically CIO. Anyhow, it's a book I constantly refer to, even with second child. There is a section on daylight savings (or whatever you call it over there). I'll see if I can quote some of it for you. Sorry I don't have any personal experience with this.
"When you move the clock time an hour earlier or later, continue to sleep your child according to the new time. If her bedtime has been about 6.30 p.m. and you moved the clock forward an hour so her old 6.30 is now 7.30 p.m., still put her down to sleep at the new clock time of 6.30 p.m. The reason you can ignore the time change is because a lot of social cues in the family such as active or quiet times, meals, bathing, outdoor play time is adjusted with the time change, and these social cues help regulate your child's sleep schedule."
I hope you understood all that!
We are having issues with DS2 atm as well, previous excellent sleeper. He has been "off" since last week, after getting his chicken pox vaccination. Only 2 weeks earlier he had tonsillitis, very nasty. We've also been having some SA issues, but I think we're coming out of that now. All of that culminated in taking up to an hour to go down for sleep at bedtime

Never before experienced this with him. I thought since he was stuffing around, we may as well drop that last nightime bottle as well....so in some respects it's been a good thing

Now he's all over the place, sleeping up to 13.5/14 hours overnight (

) and wanting to go for his nap close to his normal time of midday, even after only 3.5, 4 hours up. WT??? Anyhow, seems happy otherwise. Think he's on the verge of a bit of a language explosion/developmental thing - and/or molars. Sorry to waffle, just letting you know you're not alone and why I rarely get time to get on the board of late!
IMO, I don't think you need to go right back to 5, 5.30 p.m. bedtime - stick with the 6.30 time for the moment and just ride out this illness. Did you try the vaporiser? Have you tried a dose of Panadol before bed? Wishing Maya a speedy recovery...xo