Hi Iveson, If you can afford it definately go wfp. I started window cleaning last year and I was lucky enough to have enough redundency money to buy wfp equipment and dont regret it one bit.
I often see a trad window cleaner that works on the same estate as me and I would say that I am easily twice as fast as him. I would never purposely take customers from him but I have had calls from home owners asking me to do their windows because of the privacy of wfp and the frames, sills and front doors get done by me.
Doorknockers are still going but try canvassing yourself. If you can persuade your girlfriend/wife, sisters, female friends to help all the better because from what I have read on this site women are more successful at canvassing.
best of luck