Is that air or co2, and is that at walkon or standard rates?
I went to DF once with my own marker and gear when I had to wait for my son who was playing .50 calibre. The rate was their standard punter price - only £8 for 100 balls.
They provided me with air tank and my marker had to be in their storage area all the time when not in play. Some DF sites use CO2 and others use HPA.
Their general policy is to use their site bottles but it is up to the manager and they may allow you to use your own if you do not want or cannot use CO2
but the downside may be that they do not have air compressors so you may need a few tanks with you. I never heard of DF doing proper walk-ons.