Ok so in the provisioning template these are the settings responsible for Distinctive Ringing:
<!--########################################################-->
<!--### Distinctive ringing ###-->
<!--########################################################-->
<!--# Setting for distinctive ringing base on altert info -->
<!--# info=external call from external line (no reformatting has been applied)-->
<!--# info=international call from external line, reformatting detected international call-->
<!--# info=national call from external line, reformatting detected national call-->
<!--# info=local call from external line, reformatting detected local call-->
<!--# info=queue call from queue-->
<!--# info=ivr call from IVR-->
<Ring1 group="Phone/Ring_Tone">n=Classic-1;w=3;c=1</Ring1>
<Ring2 group="Phone/Ring_Tone">h=external;w=3;c=2</Ring2>
<Ring3 group="Phone/Ring_Tone">h=international;w=3;c=3</Ring3>
<Ring4 group="Phone/Ring_Tone">h=national;w=3;c=4</Ring4>
<Ring5 group="Phone/Ring_Tone">h=local;w=2;c=1</Ring5>
<Ring6 group="Phone/Ring_Tone">h=queue;w=2;c=2</Ring6>
<Ring7 group="Phone/Ring_Tone">h=ivr;w=2;c=3</Ring7>
<Ring8 group="Phone/Ring_Tone">n=Simple-4;w=2;c=4</Ring8>
<Ring9 group="Phone/Ring_Tone">n=Simple-5;w=2;c=5</Ring9>
<Ring10 group="Phone/Ring_Tone">n=Office;w=4;c=1</Ring10>
If you want to disable distinctive ringing and allow users to control there ringtones normally you will need to change the settings in the template to these and re-provision the phones.
<!--########################################################-->
<!--### Distinctive ringing ###-->
<!--########################################################-->
<!--# Setting for distinctive ringing base on altert info -->
<!--# info=external call from external line (no reformatting has been applied)-->
<!--# info=international call from external line, reformatting detected international call-->
<!--# info=national call from external line, reformatting detected national call-->
<!--# info=local call from external line, reformatting detected local call-->
<!--# info=queue call from queue-->
<!--# info=ivr call from IVR-->
<Ring1 group="Phone/Ring_Tone">n=Classic-1;w=3;c=1</Ring1>
<Ring2 group="Phone/Ring_Tone">n=Classic-2;w=3;c=2</Ring2>
<Ring3 group="Phone/Ring_Tone">n=Classic-3;w=3;c=3</Ring3>
<Ring4 group="Phone/Ring_Tone">n=Classic-4;w=3;c=4</Ring4>
<Ring5 group="Phone/Ring_Tone">n=Simple-1;w=2;c=1</Ring5>
<Ring6 group="Phone/Ring_Tone">n=Simple-2;w=2;c=2</Ring6>
<Ring7 group="Phone/Ring_Tone">n=Simple-3;w=2;c=3</Ring7>
<Ring8 group="Phone/Ring_Tone">n=Simple-4;w=2;c=4</Ring8>
<Ring9 group="Phone/Ring_Tone">n=Simple-5;w=2;c=5</Ring9>
<Ring10 group="Phone/Ring_Tone">n=Office;w=4;c=1</Ring10>
<Ring11 group="Phone/Ring_Tone">n=Pulse;w=5;c=1</Ring11>
<Ring12 group="Phone/Ring_Tone">n=Du-dut;w=6;c=1</Ring12>