Those books that say 3 days are lying!

OK, I put DS to bed. He wakes up one sleep cycle later (30-45 minutes usually) and I pat him back to sleep. I rarely need to pick him up and I never feed him because I want him to just sleep through this one and so I can go out once or twice a month at night! Well, that and sit and enjoy myself of an evening without having to go to his bedroom at 8.30ish. Only or 2-3 minutes, 10 at the absolute outside.

I've done this for about 2-3 weeks, maybe more. When will he get the picture and not wake up? He sleeps another 2-3 hours after this wake-up so why does he wake up now?

Day sleeps rarely happen: today he slept for 40 minutes 11.15-11.55, then 20 minutes around 3.30ish. He tends to sleep 8pm-7.30am with a few wake-ups for feeding (usually around 11 and just pre-dawn, then up for the day at 7.30, maybe more if he's hungry) and has a big dinner before bedtime to fill his tum (potatoes and banana... sleepy foods, according to the so-called experts).

So how do I get him to drop the 8.30 wake-up?