@Romain ***
The return of the 90-day notification is very hard to pick as far as time taken is concerned. I've being doing it this way for years, as the online system can flunk at times I don't trust it, but I've had the notification back in as little as seven days and at the other almost six weeks, so it all depends how busy they are. I always take a photo of the completed TM47 form, and the envelope with the EMS sticker and the dated receipt for postage. I've never had a problem, but you never know! There's always that first time when someone wants to see the 90-day report