ok firstly £650 is what i'd require and have put that in for my time.
having looked over the site i can say the following:
the 2 domains are resolving to the same location which is a google sites site.
the homepage reads like a todo list - un-seo-friendly!!
the about page is horrendously bad for UX - un-seo-friendly!!
the services page is similar, only 1 internal url
none of your reviews are wrote in code that search engines would reference as "reviews" making them pointless - un-seo-friendly!!
the qualification page bares little relevance other than keyword stuffing that search engines hate these days - un-seo-friendly!!
the contact page doesnt use any tagging, let alone data tags for contact details - un-seo-friendly!!
the "computer repair [town]" pages look like a carbon copy of something like wiki-pages on the locations which search engines know as cloned data - un-seo-friendly!!
i appreciate that you are highly knowledgeable in large-scale (corporate) IT solutions though find your logic on requirements quite poor.
i recommend a reasonably simple wordpress solution for your website upgrade. featuring a homepage, services page(s) (with overview page), about, reviews, contact.
i also recommend the implementation of several KEY pluggins and possible (basic) training in the usage techniques.
further to this i will provide key business listings and advise you on how to build your brand on business listing sites. this is hugely overlooked and as effective as the onsite stuff