Is it expensive to replace a starter motor?

My oven (electric) was tripping the electrics in house so got someone out and they said starter motor has gone. They said they would order one so told me over a week ago it will be £170 for part and to fit so I said ok order it and am still waiting for a call back. Apparentley the part was obsolete so have had to order different part that he is 99.9% sure will fit! Oven is a Brandt and is about 7 years old ( so I was told)