Yes a split pair - I presume you have a VDSL Interstitial plate at the current master socket?
Is the reason for wanting the master socket moved so that you can place the Openreach modem on the end of it? Is there any need for the telephone to work?
If you want to ignore the rules completely the best solution to having the master socket in the position of the current extension socket, and the risks of a charge for fixing this if there is a problem later that Openreach think is caused by the changes you made.
1. Get some gel crimps
2. Remove the existing master and and extension, noting which wires are connected to A & B
3. Gel crimp the A to the blue with white stripe that goes to the extension location
4. Gel crimp the B wire to the solid blue wire
5. Place the master socket at the extension location and wire blue with white stripe to A
6. Wire the solid blue to B
7. Connect back the VDSL faceplate and master socket faceplate
8. Openreach modem and phone should work in this new location.
9. Connect the orange with white stripe to pin 2 on the back of the master sockets split face plate
10. Connection solid orange wire to pin 5 on the back of the split face plate
11. Where the old master socket was located connection the orange with white stripe to pin 2 on the extension socket
12. Connect orange to pin 5
13. Screw to wall and it should work as a telephone
Failing all that you can just removed the VDSL faceplate and see how using old fashioned microfilters fairs, if you aren't worried about speed