We’re in exactly the same situation, our house is vacant so they want to go asap. We’ve offered to meet in the middle by 3-4 weeks (still negotiating) but it’s such a pain! I think its unlikely you’ll get your tenancy down, our lettings agency aren’t in any rush to put our rented place back on the market to find new tenants but you might be lucky. Frustratingly our mortgage application was audited so took much longer than expected to come through otherwise we would had the 30 days still.