...my only worry is that i bought a extended warranty for my car, from the dealer and think that fitting them elsewhere may void the warranty...
Can't see a problem.
You've had the car serviced and MoT'd at the dealer, so you have presumably complied with the conditions of the warranty.
Worse way, if they ever realise the pads had been changed, they might try to wriggle out of a claim for something brake-related.
But most stuff like that would go down as wear and tear and not be covered anyway.
Get the pads changed where it suits you best.
|