My thoughts

I do a lot of work around Swindon, I would say 40% or more of the many new houses have standard  tails running through the fabric of the building without additional protection.

If you are running the tails through the loft space, say clipped to beans or something, away from the ceiling below I wouldn't consider them buried in the fabric of the building to depth of less than 50mm. Inside a wall is at a depth of more than 50mm. 

My understanding is that using SWA is so that nails etc come in to contact with the earthed armour and live conductor at the same time, SWA is never going to stop a nail or a screw, it will just go through a gap in the strands.If SWA is used (not sure RCD protection is required, need to check the regs). thinking logically if the cable is damaged fault current will be connected to the armour and not the person holding the drill. I would think the pragmatic approach is protection by a 100mA time delayed RCD, it's what I have done in the past anyway.

If you can get conduit in, could you buy some 3mm thick capping from a steel merchant and use this instead, I am informed this is what some house builders do.

Then I would have a switched fused isolator in a steel case, mounted in the meter cabinet, proteus is about the smallest I have found, then replaced the switch with the RCD. Get rid if the DNO's isolator switch as it's not required any more, SSEN have a policy where they allow registered electricians to break the fuse seals provided they replace them and apply a sticker with  their details to the fuse. EV installers end up cutting the seals on fuses in over 50% of installs, there is no way the DNO's can keep up.

Tails from the meter to the fused switch, swa terminated in the fused switch.

Only really need to be concerned if the SWA is going to be at 90C where it's terminated. If loft insulation etc is increasing temperature is there enough cable run between the insulation and the terminations to dissipate the heat.

Most EV' charge points end up being connected to a seperate DB close to the incoming supply, tails split in henley blocks inside the meter cabinet. All depends on where the EV charge point will be located. In general a separate DB aliviates thermal issues  with RCBO's over heating due to constant load and proximity of other loaded devices. Typical RCBO at full load dissipates 15 to 20 watts. 

I have a similar issue to deal with on Friday. 10m run either under the plaster of a dot and dab wall or inside a ground floor ceiling. Whatever I end up doing will be better than the current situation with the DNO's cable running under the plaster board protected by a 315A fuse.

My thoughts

I do a lot of work around Swindon, I would say 40% or more of the many new houses have standard  tails running through the fabric of the building without additional protection.

If you are running the tails through the loft space, say clipped to beans or something, away from the ceiling below I wouldn't consider them buried in the fabric of the building to depth of less than 50mm. Inside a wall is at a depth of more than 50mm. 

My understanding is that using SWA is so that nails etc come in to contact with the earthed armour and live conductor at the same time, SWA is never going to stop a nail or a screw, it will just go through a gap in the strands.If SWA is used (not sure RCD protection is required, need to check the regs). thinking logically if the cable is damaged fault current will be connected to the armour and not the person holding the drill. I would think the pragmatic approach is protection by a 100mA time delayed RCD, it's what I have done in the past anyway.

If you can get conduit in, could you buy some 3mm thick capping from a steel merchant and use this instead, I am informed this is what some house builders do.

Then I would have a switched fused isolator in a steel case, mounted in the meter cabinet, proteus is about the smallest I have found, then replaced the switch with the RCD. Get rid if the DNO's isolator switch as it's not required any more, SSEN have a policy where they allow registered electricians to break the fuse seals provided they replace them and apply a sticker with  their details to the fuse. EV installers end up cutting the seals on fuses in over 50% of installs, there is no way the DNO's can keep up.

Tails from the meter to the fused switch, swa terminated in the fused switch.

Only really need to be concerned if the SWA is going to be at 90C where it's terminated. If loft insulation etc is increasing temperature is there enough cable run between the insulation and the terminations to dissipate the heat.

Most EV' charge points end up being connected to a seperate DB close to the incoming supply, tails split in henley blocks inside the meter cabinet. All depends on where the EV charge point will be located. In general a separate DB aliviates thermal issues  with RCBO's over heating due to constant load and proximity of other loaded devices. Typical RCBO at full load dissipates 15 to 20 watts. 

I have a similar issue to deal with on Friday. 10m run either under the plaster of a dot and dab wall or inside a ground floor ceiling. Whatever I end up doing will be better than the current situation with the DNO's cable running under the plaster board protected by a 315A fuse.