In direct discrimination, the focus is on the motivations and knowledge of the individual decision maker.
The EAT has held In Gallop v Newport www.bailii.org (part of the same litigation as the 2013 Court of Appeal decision) that on a direct discrimination claim one looks just at the motivations and knowledge of the individual decision maker. Accordingly knowledge of a disability by other employees (including OH) could not be imputed to the individual. More: Knowledge of the disability under EqA>Direct discrimination.
The decision is not authority on the more important issues of reasonable adjustment claims and discrimination arising from disability. As regards knowledge of OH in the context of those, see Disability: Is the employer treated as knowing what OH knows?