Tenant gave us notice but now refuses to move out!

Our tenant sent a message by text on 16 July to say she had found another property and wanted to move in about a months time. 

I started viewings on the property and the current tenant suggested a moving date of 25 August. Our new tenants were due to move in 1 September and have given notice to leave their rented property by 24 August, they then go on holiday for 1 week. I confirmed the leaving date and rent with my current tenant by letter, hand delivered and she had no issues with it.

My current tenant text yesterday to say that the new landlord is applying for a new heating system to be fitted into the house and has arranged an inspection for the proposed works for two weeks time.

My tenant won’t give me a date to move out now and said she has nowhere else to go.

My new tenant/s are at their wits end as they have nowhere else to go and and she is 4 months pregnant.

Is my only option to serve a section 21 notice and wait 8 weeks to apply for a court order???

Current tenant is on a periodic tenancy paying two weekly in arrears.

No deposit was taken as we knew the family.

I really don’t want to lose the new tenants as they are really nice.

What can I do???

I really need some advice and hope somebody here can help.

Thanks in anticipation.

Susan Owen