The only other thing I can suggest is to maybe try settling him for a sleep in his cot/cradle before you think he's tired in the day. As Kelly said, recognising tired signs is not something that happens automatically for any parent, it is something that takes time and it is a common stumbling block for many parents who have trouble settling their children. An alternative view is that some babies simply don't do a good job of letting their poor, long-suffering parents KNOW when they're tired! Sometimes, putting them down when they are awake and happy can lead to some success, as it turns out they actually ARE tired but are simply fighting it and staying bright-eyed and bushy-tailed. Does Lachlan lie and play happily if he's not being cuddled? If so, when he's been up for a few hours (and has been fed and is dry) put him in his cradle/bot/bassinette while he is happy and let him be. If he starts to cry, try the usual pat on the bottom, aviod talking, avoid eye contact, quiet "shooshing" or repetitive noises, and see if he settles.

Another thought - does he sleep better on his tummy? May God strike me down for suggesting this, but maybe he might sleep more securely on his tummy. I'd avoid this, though, if he has any risk factors for SIDS or respiratory problems (smokers in the house, a history in one or both parents of severe asthma, other children with serious respiratory problems, or if Lachlan is sick or unwell) and make sure the cot is safe (firm mattress, no pillow, no toys, flat, and Lachlan dressed warmly with light coverings). Molly was a difficult sleeper until we a) moved her into her own cot out of our room, and b) gave in and let her sleep on her tummy.