As far as I am aware NVQ Level 3 is not normally enough to satisfy the language requirement for UK citizenship. The Home Office usually require a degree which would correspond to a qualification at NVQ Level 6.
You do not have to wait for a whole year. You need to wait at least a year from the day you automatically acquired Permanent Residence status, but not 12 months from the issue date of the PR confirmation document.
If you would like to apply immediately after receiving your PR confirmation document, you should use a qualifying period for your PR application which ended at least a year ago, e.g. Dec 2009-Dec 2014.
The caseworker dealing with your application will record the date you acquired PR in the CID (Caseworker Information Database) and the person dealing with your application for British Citizenship will then be able to access the date you got your PR via this database.
You cannot apply for PR through your employer but if you were working continuously you just need to provide 5xP60s or/and a letter from them confirming your employment plus some additional documents confirming your residence in the UK (in case your employment wasn't full-time), easy peasy

All information given is just my opinion as a member of this forum and does not constitute immigration advice.