Normally the quickest way to deal with a problem is to contact the Local Authority direct. If this does not produce results then it may be appropriate to use the Fill That Hole website.
Use FillThatHole.org.uk to zoom into any road in the UK, mark the location of the defect, and the CTC will let the authority know about it, which then has a duty to take action. It takes no longer than 2 minutes to use, and it's possible to include photos, measurements and other useful information, which other people will be able to see.
www.cyclebeast.com