Dynamic Search Facility - onsale.ie

We have are looking to hire a company who has experience in building out comparison shopping / affiliate websites in CodeIgnitor/myphp databases. Sizing of up to 500K live products. If you don't have this experience, please don't apply. We are rolling out a new website ([login to view URL]) and the dynamic search facility is partially working - see here : [login to view URL] There are 4 variables, (discount, price change, category, brand); not including the main department (e.g. Health & Beauty). The use case is that where this is a change in one variable above, the numbers of products in each of the other variables will change (and their scope - e.g. If category changes to 'Skincare' the relevant brand names will change as will the discount and the price range applicable). You will see we are adopting SEO URLs. In addition, we will need to employ caching of product counts so that search can be efficient and when product tables in particular are updated each night, the table will run slowly; hence caching of product counts in each category, brand needs to be done so as not to slow the search and cause timeout. This is because when product cron routine updates overnight for any product the internal DB cache is cleaned for all SQL cached for this table. Going forward we will have other requirements such as - Price History feature - Rewrite Retailer Feed ingestion (it is on [login to view URL], but eventually we will add directly to onsale,ie). For now please quote for the above only. Please show examples of your work with comparison websites with dynamic search working. References will help.