It seems that as a matter of routine in UK, CO hand out compensation claim forms in the event of delays. Although I don't know in what kind of timescale these are dealt with. I have 2 outstanding claims (a cancellation & a 5.5 hr delay with a missed connection).

I would write or email. But as Sbm12 indicated your rights are enshrined in EU law and hence no need for the 'scare' tactics.