Tenants want to move IN but on business visa /Turkish THAT expire?

Dear all

Hope you can help
My current tenants are leaving at the end of this month.

I advertised the property and get a few responses.
One couple visited the property, liked it and the same day said they offered that they would like to move on 02. November what would be great since no void period (only 1 day)

I used reference Rent Guard and after 3 days report arrived.

To cut a long story short…they are Turkish citizens, with a Turkish Businessperson visa.
Their Biometric Residency Permit, which was shown, is expiring 05 11 2020 and they have applied for an extendable visa and having an interview on 19 10 2020.

To be fair, they have been transparent, they screenshot me their bank balance (9k), they are self-employed and they opened a company where the wife is acting as Company Director.

Both working in IT.
Now, my question is why they did leave it so late to apply, or maybe it takes like forever to get an interview at Croydon, because we can not sign legally the contract till their status is clear.
The current landlord left them great feedback as reference paying £ 1600 pm-now would be £ 1450
Income couldn’t be verified on the report since it is coming from Turkey.
Is there anything I should be aware of here because I said would like to meet them tomorrow in person(the current tenant showed them the flat)
At the same time, I don’t want to leave It too late and losing potentially other offers since I paused advertising.
And most importantly-once they do the interview on 19 October do they get an answer straight away confirming they can stay longer or not?
If not, how can they rent anywhere?
Thanks for your help.

My understanding is that if the tenancy starts before their current visa expires, you can rent to them for 12 months, provided the Right to Rent check was carried out no more than 28 days prior to the start date. If you want to check this, you can call the Home Office helpline on 0300 069 9799