Hi Ultraviolet
Your assessor is certainly letting you down.
It seems that most assessors visit monthly but I visit every two weeks as I find this keeps the motivation going and ensures we don't end up with mountains of evidence to wade through. Also, it is unfair to the candidate to leave him/her for weeks at a time producing evidence that may not be sufficient or relevant. Another good practice is to always arrange the next visit at the current visit then everyone knows what is going on.
My candidates do not take any more than six months for a straight NVQ, usually less, unless there are particular issues when the candidate requires additional support.
Get your manager to contact your training provider and ask for better support from your assessor.
Awarding bodies insist on assessors supporting candidates by making regular visits and clearly explaining the NVQ process what is expected of them.
Hope this helps.

Dave
PS Has your assessor explained the complaints and appeals procedure to you?