There’s quite a few insurance companies who’ll set their premium rates for new customers much lower than their rates for renewing customers - so they’re effectively ‘buying in’ the new customers, and the loyal, existing customers are subsidising the new customers’ lower prices.
@Wilkesy; if this was your first year with Hastings, that might be what happened; they charged you a relatively attractive first year premium to get your business, but were looking for a significant increase in premium when you wanted to make a change to your policy. A word of warning - I don’t know if Admiral use the practice of ‘buying in’ new customers, but if they do, they may quote you a significant premium increase when your policy is up for renewal in 12 months time. So be sure not to let your policy auto-renew;
shop around for a competitive price!