Tenant not giving keys back and gone AWOL at inspection?

I provided my tenant with a Form 6A / Section 21(1) form in October with the agreed date of 3rd Jan 2019 to vacate the property. At the time, she seemed agreeable to the arrangement and was understanding of my change in circumstance which meant I needed her to vacate the property.

I liaised with my tenant about when to arrange the check out inventory inspection and we agreed on 3rd Jan morning so that she could hand the keys over to the inventory clerk and allow them to proceed with the check out inspection.

However, she was not at the property on 3rd Jan nor did she turn up to meet the inventory clerk. Both myself and the inventory clerk have tried to contact her by phone/text/email several times to no avail, in order to rearrange the check out as well as arrange handing over the property keys.

Given that she still has the keys, and hence access to the property, I cannot arrange for the checkout inspection to be done.

I was due to move into the property myself on 7th Jan but now am unable to do so.

Is anyone able to offer some advice as to how best to proceed with regards to getting the keys back and getting the check out sorted so that I can organise the deposit to be returned to the tenant and organise moving in myself?

I have read a mixture of articles online, some saying the tenant is liable to pay rent until keys are returned, others saying that she may try to claim that I have unfairly evicted her and that this can land me in jail!

I will also need to get the locks changed before I can arrange the check out – in a normal situation I would do this between tenants anyway but as I cannot even complete the check out now and need to get the locks changed as a matter of urgency, is this something to charge to the tenant?

Thanks in advance!

Kay