That mk4 SSFP plus NTE (i.e. faceplate + master socket) is the newest and most user-friendly one, and it will be good for VDSL2 (=FTTC) too so it's future-proof.
To fit it, as it is a new master-socket, you will legally have to get an Openreach engineer, as no one else is allowed to touch the wiring behind a master socket. But since you're relocating the master socket anyway, just get the whole thing fitted at the time, as you said.
If you have a choice of where to park the master socket, keep the length of house-internal wiring from the outside world to the master socket to a minimum, as that reduces the chance of it picking up any interference. And always keep the modem near to the master socket. The length of other network cabling, such as modem-to-router cabling and network cabling between router / switch and pcs doesn't matter as this will all be reliable CATX cabling which is interference-proof as long as it is not next to mains or if it's double-screened/shielded (very interference-proof).
Of course, many people don't have such an easy choice of where to park kit. But it's fine to separate modem and router by a long distance, if you want to. Just use highest quality CATx network cable for the job.
As for house-internal wiring to the master-socket, the engineer should be using the proper BT-spec twisted-pair cabling for this, and nothing less. This is very important. It's recommended to use a real OpenReach engineer, to stay legal and for peace of mind. Someone will remind me of the BT part code for this type of twisted-pair cable.