It’s not the Main issue as far as ranking. Search engines like Google will use the descriptions sometimes (less and less now) for what they will display on a SERP(Search Engine Result Page). Google has stated repeatedly that they don’t use descriptions in ranking. And they will only use the meta description tag on the SERP if it is accurate and matches the what the user is searching for.
Descriptions are easy to add with no extra addons, and use them. Page inspector> Meta Tag settings:
Don’t need to do anything special, and you don’t need any addons to produce the xml site map Google is looking for. Advanced settings, check the Generate Search Engine Sitemap box (default is checked). This will place a xml sitemap in the root directory.
BTW: You have one already: http://pc-healer.co.uk/sitemap.xml
I took a quick look at the URL you posted above, and I don’t see any headings or pages that even mention the words ”PC Repair”.
I see ”Healing your PC” a lot, but not ”PC repair”.
On the about us page, you kind of mentioned repair in the text of a paragraph
PC/laptop/MacBook repair and support service
If you want to be found in search results for a phrase, you probably need to have that phrase somewhere on the site. In fact if it is a competitive phase then you might need a page about it.
There is no SEO Vudu magic to getting found. Any SEO tricks just don’t work.
The reason Google isn’t showing your pages on SERPs is content related. There is no Content for those types of phrases.
If you want to be found for PC Repair in Reading then maybe have a page called something like pc-repair-reading and make sure you have things like the h1 tag, title, lots of content about PC Repair in Reading.
Since you are a local Business, look at some information on Local SEO. Things like Local Listings can have a greater impact on a page ranking than metadata does.
As A general rule, if the end user can’t see it, it probably won’t affect your pages ranking at all. It might impact what the search engines display.