Paul,
In theory, this MAY be fine. A large site like that has a lot of age and authority.
How many people actually use it to look for a cleaner however, is a different story.
Using their accountant in Plymouth as an example, that page does not figure in the top 1,000 Google results for their keyword.
You may get people who are looking at the local site find you but I cannot see that many doing that. Page impressions is meaningless. You coul be in 1,000th position and the page impressions could be really high. It's just that nobody creating those impressions would ever see you.
Like gambling, if you can afford to lose the money, fair enough.
If in doubt, contact a few people that are already using it and see what they think.