I am 48 been running 2 years have a 10k time of 46mins and half marathon of 1hour 50 mins but in my first marathon struggled to finish in just under 6 hours. My legs just wouldnt have it. My second marathon is 2 weeks away, have been doing 15 mile runs on my rare days off and shorter runs when im working any ideas?

I think you really have to increase your milage, especially on your one long run a week.
It sounds like your freetime is minimum but the only way your going to get a faster marathon is by increasing your long run and weekly milage.
If you running a 10k in 46mins at 48 yo, theritically you should be able to run the half in 1hr 40 and the full in a 3.30.
You probaly feel your legs cannot do it you do not have the glycogen stores in your legs to take you the full 26miles.
To get these you need to up the long runs to at least 20-23 miles.
At 15 miles your still over 11 miles short of a marathon and that is going to hurt.

I certainly agree with cregneebaa's post. This close to the marathon, there is no further training you can do - you'll have to do the best with what you've got. At this point, you'll just want to be very conservative in pace going out and wait until mile 18 or so to pick up the pace if you're feeling good.

thanks for all help. im running the cornish marathon on 19 th nov its a tough hilly cross country out and back course with lots of water and jelly baby stops. This time i will eat more before and during but with a pb of 5h55m to beat i should be ok. Ihave committed to run a marathon at least once every calender month for ten years and the only one in december is the luton on 3rd dec !! thanks again for the help ill keep u posted