Originally Posted by
laura_d77
thank you. Will do. On their web site it was we have to wait 8 week's though. Do we need to wait, or just start the process now?
You have two choices - either go to MCOL (Money Claim Online, a small claims court process), for which you'll need a physical UK address (you can 'borrow' one from a friend for correspondence, you don't have to actually live there).
Alternatively, you can use the dispute resolution service, CEDR. This will probably take longer to get a decision from.
In either case, to speed the process, formally write back to BA asking them to confirm that "this is their final offer and the decision will not change". That will allow you to either refer to CEDR immediately (free) or issue MCOL proceedings (a fee, which you recover if you win).
You should note that your delay compensation claim is based on arrival (doors open) time, not departure, and therefore you are working on a delay of 3h12m.
Some caution is therefore needed - if BA can show that staff sickness (or other causes generally held as extraordinary such as ATC/weather delays) took the delay below the 3 hour time limit for compensation, then they are correct and nothing is due. There are potentially other legal arguments here - if the staff sickness was in parallel with the maintenance, for example, BA couldn't claim that as they would not then have taken all reasonable measures to mitigate the crew issue when they had extra time to resolve it.
So, it may be a little more complicated than you think ...