service work by 'independent' during warranty period

hi, appreciate that 'under European law' etc etc, manufacturers are supposed to be obliged to uphold warranty claims even if service work during the warranty period hasn’t been undertaken by authorised service centre but by recognised ‘expert’ but was wondering if anyone had ever had any issues with Ducati on this point? Just that the S4RS needs a £4-500 service from ‘dealer’ but that my local expert could do it (arguably better!) for less than half (the well respected Carl Harrison in Norfolk). But bike is still under manufacturer’s warranty period so should I spend the extra for the ‘stamp’.......??? Any thoughts??