Website redesign and onlie shop

I currently have a website www.fairlawnsartificialgrass.co.uk It has been very productive with regards to drumming up installation work on the west midlands but there are elements that are not up to standard with competitors websites. i am now looking to get a professional looking website and focus on getting up there with the UKs top artifcial grass companies as installers in the west midlands and suppliers of artificial grass and accessories to the uk market. I would like a shop with approximatley 15 to 20 products on there with the option to add more in the future. I Also want to have a trade login for trade customers
to access trade prices after being approved by us here at fairlawns. Public customers will see the same products but at full retail price and this section will be the default shop. The current website platform is on ionos. The new website must be super responsive, Secure, SEO optimised and easy to use. I want to make sure that the url structure is properly taken care of so we dont lose ranking on keywords or pages that we already rank for. At the same time i dont want any redesign to hinder my current installation enquiries as this is currently our main line of work.
The new website must convey everything that the current website does. Products prices to be displayed Ex VAT on trade section and including VAT on retail (default) section.