The dealer gets a fixed handling fee from Motability, so it makes absolutely no difference to them what the AP is as it goes to Motability, not them. As the Motability ‘order’ isn’t an actual order, it’s just admin, most good dealers will re-do the admin with Motability so that you pay the lower AP. Takes a matter of minutes and doesn’t affect the actual order (which is between the dealer and Renault U.K.). My BMW dealer did it without me even asking them to when the AP dropped £100 the week after we ordered.
However, it is most unusual for Motability to process order admin for a model of car that is not listed on the website. In fact, I’ve never heard of it before so, in this case, I’d also be a bit suspicious. I guess if the RS line exists and you want it, keep quiet, hope that you get it and accept the higher AP. Alternatively, if the Engineered version still exists, is still available to order, is still on the Motability website and you would prefer that model, ask the dealer to spend 5 or 10 minutes changing the admin and save yourself £200.