Usually recommend NPTC. Try to do basic cross cutting and maintenance and small felling at the same time. From memory it takes around 5 days.
I think that's CS30 and 31
Small trees should get you to 350mm diameter.
You're probably looking at upwards of £600 for both including the assessment -
http://www.ianmorganarb.com/arb-trainin ... d-felling/
That seems to be a fairly standard price.
If you're willing to volunteer some of your time you may be able to find an organisation which will provice some training for you. I did 2 days per week with the local wildlife trust and got my CS31 out of it. One of the local National Trust places near me (Cragside, Northumberland) used to have a scheme where they would train you and you could go and practice under supervision on their grounds. I think the local council helped fund it.
For saws - you want something designed for long days of work which will last and be reliable. We use Stihls but only because we have a local dealer who gives us a good discount. We also have a few Husqvarnas. There's often heated debate as to which is best but either is good.
We have a small battery powered Stihl and wouldn't consider it for anything bigger than maybe 20cm diameter. It's useful and lightweight so good to carry round if you don't have much to do but if I'm working all day I want something more powerful which will get the job done faster.
Our new Stihl 261's (pretty sure thats the model) are ok but they have a modern controlled carb system which doesn't let you adjust things easily and have to be taken to the dealer if they need tickover etc changing. They're ok when tuned but we've found them to stall regularly. I'd probably advise against that model.
My cousin really likes Husky saws and last time I worked for him he had a nice little one designed for home use. I think it was
http://www.husqvarna.com/uk/products/ch ... 966639901/. Whilst not as robust as their work saws (more plastic parts) it was nice and light and for regular low level work with lots of bending it was great. It had some fancy easy start system which should really be needed on a saw that size, but useful if you don't have much arm strength (although if you don't have the strength to start it should you be using it!)