gf refused fiance visa, advice please?

It sounds like they want to get married on a certain date (which is a little over 6 months from now am I right?) but they want to be together ASAP.  So I get it, although I agree that it's better to get married when you have plenty of time left on the visa.

Absolutely right springhaze.
Is it written anywhere official on the internet that the marriage visa is multiple entry?  We need to see this before planning the next step.

In your original post, you were asking about a fiance visa.. are you still refering to a fiance visa when you say "marriage visa"?

The only official place I can find it is on Garrys site

Fiance visa, as described here:
http://www.ukvisas.gov.uk/en/howtoapply/infs/inf4husbandswivespartners#Q1

But this visa seems to be refered to as a marriage visa.

Fiancée visa is multi-entry as long as you are still a fiancée, not a spouse. 

If you want to get married on a certain day, I did too, our anniversary, then just apply for the visa closer to time to allow yourself time to get the next visa afterward.  If you apply again, with the correct paperwork, in a couple of months then it should be fine.

But, then again, we went in person the day after our wedding.  Our only rush was that I had a full-time job waiting on a visa...

I still wouldn't wait until that close to the expiry of the visa - maybe we should wait a couple of weeks before entering the UK so you can still get married on that anniversary and have a couple of weeks remaining on the visa after the wedding?

Going in person costs more, but then it was done - and, in our case, our wedding and the hotel we stayed in that night was less than a mile from the PEO, so we were right there and it worked for us...

Another warning though, going in person is a getting a lot more complex.  You may not be able to get an appointement for 4-6 weeks depending on the PEO right now, who knows what it will be like in 6 months.  Plus there is the complication of the Biometrics and National ID Card that will be in full swing by then.  We don't really know how that is going to play out, though the in person description on the UKBA sites seems to say it biometric enrollment will be a 30 minute process out of the whole thing and the ID card will arrive in 5 working days.  So for those hot to trot to go work, you will have at least 5 more days of waiting.