More money does not equal more quality or safety. Just be smart when you are buying.
1 piece leathers is overkill as is the balaclava. I wear cordura (well textile) gear and although i have never come off a lot of people over here have their doubts about its safety. I think the roads in NZ are a lot harsher which may have something to do with it.
But a 125cc is going to be slow so textile gear should be fine.
Your government has set up a helmet rating site here:
http://sharp.direct.gov.uk/
While you shouldn't buy a helmet based soley on its rating (i tried!) you need to go into a store and make sure it fits and is comfortable.