Thanks to Elmo for pointing out the Bad Elf GPS loggers here: bad-elf.com/pages/compare
Unfortunately, the lowest cost two have the MTK GPS chipsets in them and so do not log the accuracy data.
The their one however, called the 'Bad Elf GNSS Survey' has the U-Blox Neo7p GPS chipset in it and is capable of logging the data we need at up to 10z. It seems to have enough memory space to log for over 24 hours and a battery to match that.
The biggest catch with it is the price at US$599! That makes it about A$850! Far too much for most I imagine, especially as you would still need two units for records.
I have contacted the company to see what they can do for us. I will post updates as I find out.
No SD card but 64mb of built in memory. Still needs a cable to download but the memory is standard type internal memory which can be seen by the file systems of Window, MacOS and presumably Linux.
I have found that the Neo7P chipset can also log the raw carrier wave data mining it is capable of RTK, differential gps and post processing techniques like a traditional Survey Grade GPS. Is this the first true sub centimetre capable consumer GPS? 
Select to expand quotesailquik said..
I have found that the Neo7P chipset can also log the raw carrier wave data meaning it is capable of RTK, differential gps and post processing techniques like a traditional Survey Grade GPS. Is this the first true sub centimetre capable consumer GPS?
Maybe I was getting carried away there with the sub centimetre. Possibly Sub 20cm with differential correction if it can produce the data suitable for RTK. 
My head is hurting! 
Sounds good , got no idea what your talking about ,but thats fine ,if it works and is water proof the cost is little at the end of the day , we all have $1000 dollar phones at the moment and thousands of dollars worth of sailing gear as well
happy days if it does all that is needed
Not waterproof: IPX4. Just lightly splash proof. :(
But. It should be fine in the normal waterproof bags we already use.
