i am a beginner in dinghies (about to do level 2) and have been offered a rocket for free from a friend. I need a boat to mostly sail singlehanded to gain experience when i get days off work in the week but could then race two up at weekends. Is a rocket appropriate? (it is free remember!!)Thanks for your help

If it's free, then get it and keep it till you are ready. Wouldn't recommend it as a first boat to helm though. They are very responsive, that is to say, move too slowly, or get it wrong, in a merlin and you swim. Would you try to pilot a fighter jet if you've just learnt to fly?

Get some one more experienced to helm for a while, and then get them to crew for you whilst you get the 'feel' of the boat.

Single handed, for a beginner I'd say no.

What sail number is it?

This all depends on where you are learning and if you can ski!
Is the water you are going to sail on calm and tide free or slow flowing? 
Can you ski? or put another way can you laugh at yourself when you get it wrong? all skiers can and will remember the first two or three days! 
So the water is safe and you have a sense of humour? go for it you will only get wet and at least there will be other club members vice comodore, comodore etc to endorse your bouancy check on the measurement certificate! 
I watched an average sailor purchase an RS 300, he struggled but 3 months later hats off to him he was mid fleet in the fast handicap fleet at the Bala August open, ok so the learning curve was steep just like yours is going to be. 
The RS is a boat that makes a Merlin look stable, launch it and it capsiszes until the crew gets in! 
So if it is safe on your water go for it.
Well that's my view anyway.

an RS300 is a singlehander though, not a merlin.

Merlins are not particularly easy to sail single-handed (there is usually quite enough to do for 2 people) unless the wind is pretty light and I wouldn't go out by myself without rescue boat cover.  The boat feels less stable than it is and the learning curve may be steep but you are not starting from scratch either, you have had some experience and tuition.  Why not see if you can get a trial sail and see what it feels like?

I'd suggest you try  it and see.

Remember that if all goes wrong you can drop everything (uncleat the  sheets, drop the tiller) and curl in the bottom of the boat. It will settle down head to wind - unlike lots of more modern designs.

If possible, choose one that has a forestay - then you can use the jib as you feel happy. 

Colin

Thanks for the replies. Mmmmmm i think i will accept the kind gift, settle her in the garage, polish her regularly. I see i will learn more sailing an easier boat to start with rather than swimming. Maybe a solo? The rocket can be there to encourage me onwards and upwards!!

I moved on to a Merlin from a Topper this 18 months, so get on with it two up! 
The wife and I did some marvelous swimming in the river, however it is character building and we are now racing in some pretty hefty winds and tidal conditions.
The boat is great and you will quickly get used to it, as you have to and we are improving every time we go out. Marvelous fun!