Welcome to FT!

21EF would not be exit rows. If you meant 12EF, then yes, these are exit rows. On the LGW fleet, avoid rows 10, 11, 12, 13, as depending on the aircraft they could end up being an exit row. Do you have a wheelchair in the booking? If so, then you can select your seats for free, and it will suitably block out exit rows. Again, avoid those rows (10-13) as the aircraft might change.

The only bulkhead seats (or front row seats) are in row 1, therefore in Club Europe.

The legroom is the same throughout.