Thanks for the valid points so far, our main concern during this conversation was specifically about distance to the edge and taking in account that here all ground movements are made by the commander (irrespective of PF/PNF status) my point was that left to right would be on the safe side in regards to lateral limits.
@stator vane
No Sir, I'm not joking, I don't make jokes before lunch time, and yes, I've been inside the flightdeck many times (albeit I only hold a CPL/IR license). Sorry if the question sounded pedestrian, but once I was told there are no stupid questions in this business, perhaps it is not the case in the UK