Scrap that - got replies back now from the three queries sent in about separate upcoming flights (word for word the same question, just changing the flight concerned - flights are LHR to DUB/ABZ/CPH):

Response one:

The reason you're unable to select the exit row on our short haul flights at present is that the Club Europe cabin is changeable in size and we block anywhere up to row 12 on the basis that we might sell the seats as Club Europe tickets. The exit row is normally on row 10, 11 or 12 depending on the aircraft, which means it could be part of Club Europe. We can't offer you seat reservation in this section unless we're sure you'll be in the correct cabin or we'd end up having to move you. If we don't sell enough Club Europe tickets the exit row seats will be confirmed as part of the Euro Traveller cabin and released for pre-booking. Until this happens I have no way of reserving you a seat in this row and can only recommend you try again soon.

Although we advertise free seating as a complimentary benefit of a Silver Executive Club membership it is not guaranteed and covered in our conditions of carriage section 5E, 5E1, 5E2 and 5E3.

Response two:

Thank you for writing to us about your boarding pass and exit row seats booking query. Exit row / extra legroom seats can be reserved from 14 days to 4 days before the flight departure time, or during check-in directly at the airport. To occupy an exit row seat, you must meet certain physical and / or age requirements. The following ba.com page explains all about the requirements for these seats, and when / how to book them on ba.com, including the pre-assignment cost: http://www.britishairways.com/inform...sing-your-seat

Response three:

Thank you for writing to the Club about your seating query. Exit row seats are available in World Traveller (economy) and World Traveller Plus (premium economy) on longer international flights. They can be reserved from 14 days to 4 days before your flight departs, or during online check-in. Exit row seats have no seats directly in front of them, and so provide you with more personal space than standard seats. If you want to request an exit row seat you must meet certain physical and/or age requirements. Bulkhead seats are usually reserved for people with infants as this is where the bassinet table is positioned, so you may not be able to reserve these.

As others have said previously, some of the responses clearly miss the point, but the first one fits with increasing large CE cabins reported in another thread. However, it does not explain why the same thing is happening on a domestic flight, and I was disappointed that the final comment was "and our T&Cs cover us anyway so tough"

Its only a seat on a short flight, so I know that I need to get a life, but if these are the small perks that sway decisions as to who to fly with, and they are being eroded away or inconsistently applied, with different people at the airline saying completely different things, then it gets frustrating and people will start to look elsewhere.