NLM is North Leicester Motorcycles
http://www.motomorini.co.uk
The flywheel thread is common to a lot of Italian bikes. I've heard it said that MZ pullers will work and are only £4. The NLM puller is something like £7.80+vat. People will keep paying £20+ for pullers on ebay. George Lane has started selling pullers made out of a better grade of steel.
The flywheel holder is just a couple of metal strips held together with a bolt and two more bolts to act as pins to fit the flywheel holes. Personally I have a big compressor and an air impact wrench and I never have trouble getting nuts or flywheels off. Battery powered versions are available.
It's important to make sure the puller is screwed ALL the way into the flywheel. Make sure you've taken the spring washer out first and that you've backed the jack screw out. If you have an air wrench then you can just hold the flywheel by hand, otherwise you'll need the flywheel holder. If the flywheel won't release, leave the tension on and warm the flywheel up. A hot air paint stripper does a great job, but watch out for a hot flywheel suddenly popping off.