You haven't added it to Google yet.
I think the site performs well, telephone number is clearly visible.
However there is nothing about you as a person, no pictures of you, is your name there. I was speaking to a customer yesterday who chose me because I had a picture of me on the main page. I was going to get rid of it but they liked it so I guess it will stay. Maybe you could include that.
Try to make the "About us Page" a little bit more personal, don't hide behind you name, make it personal reach out a bit.
As for the SEO, I dont think you have put much thought in to it. Using .jpeg are fine they look good, but google prefers text. Therefore to improve this, add a bigger description to the title tag. Currently you have nothing. I.E for the conservatory .jpeg link, You should have as the title tag text some thing like "Click here to find out about our Conservatory Roof Cleaning Services"
I would also change the url. E.g currently its this
http://www.cannockwindowcleaning.co.uk/index.php/services/conservatoryIt could be
http://www.cannockwindowcleaning.co.uk/index.php/services/Conservatory-Roof-Cleaning-West-Midlands-Areas-Covered etc
this is SEO real estate, use it.
I think you need new keywords, there aren't enough.
Also what areas do you cover, find somewhere to list them all they help search engines.
I hope all this makes sense.
There is loads more you could do it regards to SEO, search lynda.com and maybe purchase some SEO tuts
Alex