Current Eurostar cancellations

My wife and I have senior interrail passes and we are travelling out from St Pancras International on 23rd July at 11.30 for Paris.  We’ve then allowed a two hour gap to get us onto the train for Chambery at Paris Lyon and the following day travel to Torino and finally Rome.   We each have four day passes - thereby allowing us 2 days travel out and 2 days travel back and are away for 9 days in total.  I am keeping a check on the number of cancellations that are happening on Eurostar and I am starting to get anxious.  We live relatively close to London and the fare for both of us to get there is about £40.  I’m currently minded to buy tickets to London on the day we are scheduled to travel out rather than commit to using that as our travel day out of our own country.  And instead only activate our passes when we get to St Pancras just in case of a late cancellation.   I am being silly being this cautious?  We also had a nasty experience two years ago when we were travelling with passes and my wife’s pass would not appear properly just as the ticket collector appeared.  I think it had been offline for some time.   Admittedly we were crossing the Alps at the time.  However I would like some reassurance that there could be no risks with activating one’s pass at St Pancras  if one is away from a wifi signal.