Get in touch with your local British Waterways office (you'll find them in the Yellow Pages).
You should be able to get a list of your area where there are stretches of canal (s) that are not controlled by clubs. There is a Waterway Wanderers Ticket (I think what its called) whereby you pay a fee and you can fish the unleased stretches. This is aimed at the "Holiday Boating" fraternity.
In reality you can fish the unleased stretches without paying anything. In the eight years I've been fishing my local canal I've never seen a bailiff. In fact, I don't think that BW have any specific fishery bailiffs. They tend to rely on club baliffs to do the job for them (unpaid of course).
There are hundreds of miles of (in essence) free fishing available on the canal network and with a little bit of homework you can have days of fantastic sport for minimal outlay.
With regards to rod weight. A #7 Trout Rod is NOT suitable. I would recommend at least a 9/10 weight Pike Fly Rod. Yes, you might be catching "Jacks" but the canals can and do contain some huge Pike. A canal is nothing more than a long, shallow and narrow lake with plenty of fodder fish in them so the Pike have the potential to grow very large indeed.
For more info about Pike FlyFishing check out the PFFA web site
PIKE FLY- FISHING ASSOCIATION - Home
Hope I've helped you a little.
Ernie.
PFFA Membership Secretary.