Depends on “ which “ Sterling you are talking about. If it’s Sterling Insurance based in BS then a) they are a broker ( so who is the actual Insurer they have quoted you with ?) and b) have a quick look at their review score.
I have used Sterling insurance for both my daughters as learner drivers. Never had to make a claim but found them okay and easy to make pics changes via an online portal.
My son was with Sterling for his first learner car, an MR2. When he passed his test, that lapsed but the premium for a full licence was knocking on £7k so they're not exactly out to retain you.
