Change at gatwick

https://www.gatwickairport.com/flights/which-terminal.html

It appears that Norse uses the south terminal while easy jet uses both. I don’t believe there is a way to change terminals airside. So if your easy jet flight is in the other terminal you would need to clear passport control, take the tram and clear security at the other terminal. If you have checked bags then you would need to claim them and recheck.

The time you have is too tight for my comfort.

If I ad to do all that,yes I agree,the stress would be sky high

There is no longer airside connection available at Gatwick between two international flights even within the same terminal so passing through immigration would always be required. The airport suggests a minimum of 60 minutes for a landslide connection between two flights in the same terminal but that seems rather optimistic to me.

This from Easyjet regarding Gatwick Airport:

We now operate flights from/to both the North and South Terminals at London Gatwick.

Any flight with a flight number between 6300 & 6599 (inclusive) operates from/to the South Terminal.

All other flights operate from/to the North Terminal.

The terminal your flight will operate to or from is also shown on your booking confirmation.

Please make sure you check which terminal your flight will operate from/to before you travel and before booking any additional arrangements for your trip, such as parking or hotels.

if you do need to change terminals the little train is fast and frequent and free. All the doors on the exit side open simultaneously and people leave, then the doors on the entry side open and as soon as everybody is in the doors close and you get whisked to the other terminal. Windows are big and views are good. As soon as you stop, your exit doors all open and the procedure continues. A well oiled machine.

I think with 1h45 you'd be brave. No interlining to Easyjet used to be the rule, they do now interline with Norse. But I wouldn't want to risk it.

Marco and Nigel, if they can't connect airside, would they need to have ETA (Electronic Travel Authorisation)?

Yes they would. Only airports presently configured for airside transfers are Heathrow & Manchester.

Thanks, Marco. I asked not just for the OP but out of my own curiosity. :O)