Insurance Start day

Hello my renewal is about to come and i have been looking out for insurances.
I got a really good quote online that unfortunately had the start day before the renewal by a couple days. Whenever i changed it , it gave me error so i phoned and they said that quote is only available untill that day.
If i wanted to have it changed to the normal renewal day it will be nearly 2x more.
So can i start that insurance a few days early without using it?
Would that be allowed as im stating x ammount of NCB which then i wouldn't achieve as it hasn't been the full year.

As IWMTom said, you should be fine. If your new ins. co. ask you for proof of your NCB they'll usually give you a couple of days to send across the proof so you shouldn't have any issues there.

Once your new insurance starts just use that. If you happen to be pulled over or in an accident then just use your new insurance details and don't even mention the old one. If it is literally only a couple of days you could avoid any issues entirely just by not driving for those couple of days where you're covered twice.

There's nothing illegal about having two insurance policies on the same car, it just gets a bit complicated if you have an accident.

The worst part is the cheapest insurance quotes is with e.g Elephant or Admiral which they are all connected together and i woudn't be driving the car most likely anyway but i would be declaring 2 years no claim bonus when in fact i only have 1 ? Would this not come up on their system?

Who's your current provider, and who is the new provider?

As answered above , im currently with elephant and all cheap policies come back from the same company so elephant, admiral,bell etc.
I phoned them and they said that the date cant be moved up further because that quote is only valid up to 30 days.
So over the phone she created 1 and it came out as nearly 2.2x more than original. Got down to 2x but its still crazy

I'd just phoned your current insurers up and say "I had a quote for renewal with [whatever company], can you match that if I stay with you?" If they're part of the same group as your current insurers then they should match it no questions asked. No problems with NCB or doubling up on insurance then.

I'd just phoned your current insurers up and say "I had a quote for renewal with [whatever company], can you match that if I stay with you?" If they're part of the same group as your current insurers then they should match it no questions asked. No problems with NCB or doubling up on insurance then.