Is there any way of increasing this, and is it advisable?

sure! i think it's in

/etc/proftpd.conf

but I could be way off on that one.... anyway add the lines

TimeoutIdle 900
TimeoutNoTransfer 900

or whatever time (in seconds) you want.

Brandon

http://www.uk2raq.com/raqfaq/raqfaqshow.php?faq=25

Thanks guys. I went to reply last night but the board was down.

russel, that solution worked perfectly,

and ie , thanks for the great resource