I couldn't find any documentary proof, that I had signed for and given plans, specifically elevation plans. However, I found a brochure given to me by Bloor, 'Consumer Code for Builders'. The document refers to Consumer Code applying to reservations after 1st April 2017, there were previous editions from 2010. It sets out mandatory Requirements that all Home Builders must meet in marketing, selling of their Homes and after sales customer service.
Reading through it, there's a section on pre purchase information, specifically if a home is not complete; brochure or plan illustrating the general layout, appearance and plot position of the home. And some other information. That would be the elevation plans I spoke previously.
If the elevations, your brick detailing, has changed from the original build, that might be a starting point for you. Unless of course they have an opt out clause for small cosmetic changes?