Good morning/afternoon/evening FlyerTalk experts,

I am arriving into London Heathrow from Vancouver, Canada on Air Canada flight 854, arriving Saturday, April 4th, 2020 with an ETA of 11:50 am.
I am a UK Citizen, with a UK passport and will only be travelling with 1 carry on bag, and nothing to declare at Customs.
I have already booked my Heathrow Express ticket to get to Paddington.
My question is ... is there any way to know how long it is likely to take for me to get from disembarking the plane to arriving at Paddington?
I am on an 'only a small window' to potentially meet friends before getting ready for an evening event and I'd like to be able to offer a time to meet them in/near Paddington.
Any help at all will be gratefully accepted.

Cheers
Andrew