Yeah, I mentioned to DP that we needed to give them a gift and let them know we knew very soon, before MIL has a chance to say to BIL "Oh, but I told them three months ago".

We've gotten the card and will get the gift voucher this weekend. I might suggest that we drop it around this weekend as well.

And I'm hoping their new baby might make BIL realise the importance. Altho it took DP a couple of years for that to finally sink in from his side, so I'm not holding my breath!