Not for just broadband no, you’ll need to contact Shell yourself and cancel the contract - however for your own peace of mind, I’d hang on until the VM system is in and working to your satisfaction even if it means you paying for a few months extra.
Are you also taking the phone service with VM as well and if so are you porting your current number across?
Usual advice on here is not to cancel your existing BB contract until VM have installed yours and you have had the 14days "free cancellation period" to evaluate it. You need to do it. Bit more complicated if you are porting a phone number ?
Have two BB connection (bills!) for a month or so is a small "insurance" price to pay for having no internet at all if VM installation gets delayed. Not unheard of and can often be 2-3 months if they need to do some digging to remove a blockage on a new installation. Did you order a quick start pack?
-------------------- John --------------------
My services: HD TV on VIP (+ Sky Sports & Movies & BT sport), x3 V6 boxes (1 wired 2 WiFi,) SH2 in modem mode with Airport Extreme Router. On VIVID200, Talk Anytime Phone, x2 Mobile SIM only iPhones.