Thanks all

I gave in last night and rocked him to sleep again, at least he was down by 8pm and slept through

I do need to get him sleeping by himself though. I bought the No cry...for Toddlers book last week, I was a bit put off because I wasn't much impressed with her book on babies, but I will give it a read when I get the chance. As I flicked through I noticed one part saying how children who are a bit "hyper" at bedtime are overtired, my two are always sleepy at about 6pm, then half an hour later are running round like maniacs. Should I try putting them to bed so early? Although it's not always convienient, worth a try maybe?
They are both normally very active during the day, we've recently had excellent weather

and have been out loads during the day. Molly will sometimes take herself off for a nap in the afternoon when she's tired, thankfully she has nearly always slept well! It's harder with Daragh as he's not really old enough to explain "stay in bed and go to sleep" to, he just thinks I'm leaving him alone. I had been thinking of moving him to a toddler bed, his cot is 25 years old, Molly has broke many of the springs from bouncing in it and it's hardly comfy if even safe... but I'll be doomed if he learns he can get out of bed
Right, I'm off to (hopefully) start naptime, and then read the No cry sleep solution book!