I chose to pay my tax bill via my PAYE tax code I received a text asking me to pay my tax bill.

Hi,

No if the balance from your Self Assessment is included in your tax code you will be the same amount as if you had paid as on off payment. 

Thank you.

I was in the same position to OP (choosing pay through my tax code and then later received a message from HMRC asking me to pay the tax before 31 January, even though I satisfied all conditions). I phoned the helpline and the helpful agent confirmed that there was a mistake on the system, he then corrected it so that my tax would be collected via PAYE, and I can now see my self assessment accoutn shows nothing outstanding. I would have been fined by HRMC if this hadn't happened even though it was their error, so if anybody else is in this situation I urge you to contact them and not assume it will get collected by PAYE! Details on https://www.gov.uk/government/organisations/hm-revenue-customs/contact/self-assessment