Having just acquired a Merlin for the first time and only been able to get out in very light wind conditions as yet, must admit I am a little surprised as to how "tippy" it appears to be. Its a Bad Company, because one economy sized elephant and a medium gorilla, don't tell the wife I said that, need the weight carrying capacity. To be honest winds have been very light, barely 5 mph and I did expect it to be more tippy than the boats I have been sailing recently,but I am wondering if some of it is down to either, insufficient wind to power up the rig or us reacting too quickly to initial stability around the cente line, or a combination of both. Thoughts anyone.

This has been discussed before - search for "tippy" on the forum.

Most people find that when they relax and get used to it, the boat isn't really as bad as they initially suspected. Before long you'll feel right at home in it, so don't feel worried you've bought the wrong boat!

Coming from a Laser 2000, I was told "Wow, the Merlin will be really tippy". But I find its not too bad. 
YES it reacts quicker, so you need to be ready to move fast. And because of that it is very easy to over compensate (especially when both helm and crew move as we are not yet used to who has to do the balancing). The boat is ridiculously wide: so there is a lot of righting movement when you get near the deck. When the wide top-sides go into the water, it might not be fast but it does slow down the tip to allow you to react in time.
I think its all a case of getting used to it (across many different wind strengths: knowing by feel how strong the wind is for the boat, and therefore where helm + crew need to be, and knowing by listening / watching whether the helm / crew has managed to get to the position they need to be in, and therefore where you need to be keep the boat upright.

merlins are really stable boats. forgiving, and also easy to sail. maybe hard to sail well but still, they are amongst the easiest boats to chug around the course

Time in boat is the best cure, but keeping the centreboard down helps for newcomers.

I've only been in Merlins a bit over a year so it's much to soon for me to be having thoughts - let alone advice! However I sailed RS 200s before, and have definitely found my Merlin a good deal easier to control in strong winds; and we've got out of several situations where I expected a capsize. Personally I swear by the 'rig over hull' principle and canny M-gybes (or is that swear at ...?)