Hi dostbury, I think I know exactly how you're feeling - it does seem to take forever to reach a definite diagnosis, waiting for appointments with various specialists, back & forth to the GP etc,etc (and all the time you're thinking "I know there's something wrong, why won't anyone tell us what it is"). For me it's been the feeling of helplessness that's been the hardest to cope with over the last few years. I have no solution to this problem, only sympathy for your situation.
I concur with the other posters' suggestions re Citizens Advice etc & would also suggest that you investigate whether there is a local Alzheimers Society office in your area - we have had some very good advice & information from that source. Where we live there is also an independent carers charity who assist with advice, completing forms and so on - again, our local Alzheimers Society office were very helpful about providing contact details for this.
I hope you find someone who can help you to obtain the assistance you require.