Recently bought MR2292 Hysteria in Northumberland and will be restoring /renovating to get it back on the water. 
The hull is in great shape with just a tidy up needed, but the fittings need replacing and the mast was stored on the sailing club roof and the rigging has rotted.
As I haven’t been sailing dinghies for 20+ years (Windsurfer, sorry) and have never sailed a Merlin Rocket, I am looking for a comprehensive rigging guide for a boat of this age.
Any advice or books or pamphlet’s on the subject welcome.

Have a look at the 'Rigging Guide' section at the Title page this gives a few variables to get the old thought processes going. Then maybe check out Merlins at other clubs, my advice would be to start simply but leave room for the more complex systems later. theres nothing worse than seeing fittings squeezed in, buy good hardware & cordage then the sailing will be all the more pleasurable (like windsurfing !) Oh and join the class association the mags alone make it worth it.
3236 on the rigging guide is mine and I've taken other close ups of fitting set ups for others if you have any particular requirments, all the best Barry.

Look at other boats esp at Vintage Merlin Events and come along to Classic and Vintage Racing Dinghy Assoc. events too. Next one is Baltic Wharf in Bristol in November.
Check the forum events section of www.cvrda.org for details.

But even nearer and sooner is the Banbury Vintage event on this coming Saturday.  There will almost certainly some like your new one coming along and you will find all different kinds of rigging variations - see link for details.

Thanks for advice. Theres no Merlin fleet left in the North East anymore but I will try to find sombody who knows how to use one of these things!!!!!!!!