p/e seat change

hi, im returning las to lgw next week and been allocated a seat downstairs. the seating plan is unavailable on website,therefore would it be best to do onlne check in or get in early at the desk to change my seat? [there is 1 seat open on expert flyer].
thanks

[honey lamb]

I would suggest OLCI as many of the seats held back for pre-selection are released then. If no luck then I would go early to the airport to try and nab an exit row

Try OLCI but don't be too disappointed if there aren't any additional seats available. On the LGW flights the only PE seats not preallocated are exit or bulk head which are only available at a check in desk.