If you are getting comments from your own customers saying "Isn't time your prices went up" then in most they are expecting you to do so.
Mentally they are prepared for the increase, so just do.
If you were to lose, 10 at your base rate of £5 and gained 10 at new base rate of £6, you're £10 better off, not to mention that those new ten custys may want some additional services, such as gutter cleans on top.
Either way, you, your pocket (and if you have one missus) will be better off !