I see the actual regulation is quite clear no non-1363 plugs or equipment isn't put on the market

The "The Plugs and Sockets etc. (Safety) Regulations"? as I read it the requirement applies to appliances sold to consumers on the UK market (whether manufactured in the UK or imported) - as I read it there's nothing to stop a consumer buying something abroad and bringing it with them as a personal possession into the UK (quite reasonably - it just wouldn't work to say people couldn't bring their laptop PSU or phone charger or 101 other things with them into the UK).

To my mind foreign plugs can't safely be inserted into UK (BS 1363) sockets - even if they can be made to physically fit, the lack of  fuse would be a safety issue. Travel adaptors might be one option, but their quality is often very dubious in practice. Far safer to have suitable compatible socket available. So I reckon 553.1.5 (iii) can be invoked,

   - Andy.

I see the actual regulation is quite clear no non-1363 plugs or equipment isn't put on the market

The "The Plugs and Sockets etc. (Safety) Regulations"? as I read it the requirement applies to appliances sold to consumers on the UK market (whether manufactured in the UK or imported) - as I read it there's nothing to stop a consumer buying something abroad and bringing it with them as a personal possession into the UK (quite reasonably - it just wouldn't work to say people couldn't bring their laptop PSU or phone charger or 101 other things with them into the UK).

To my mind foreign plugs can't safely be inserted into UK (BS 1363) sockets - even if they can be made to physically fit, the lack of  fuse would be a safety issue. Travel adaptors might be one option, but their quality is often very dubious in practice. Far safer to have suitable compatible socket available. So I reckon 553.1.5 (iii) can be invoked,

   - Andy.

 AJJewsbury  Isn't the socket-outlet covered by Regulations 4(1), 5 and 10(1), i.e. standard socket-outlets 'ordinarily intended for domestic use' (as it's put in the legislation) should be to one of the standards in Schedule 2 (items 1 to 3 for socket-outlets of course)?

BS 7671 requires all products to be "standard" - yes, you can choose a national standard from elsewhere in the EU, offering equivalent safety (and shuttered), but in saying it's a "standard socket-outlet" aren't you then really saying you ought to choose a standard from Schedule 2?

That, of course, is a debate for legal professionals ... I'm just cautioning the legislation may potentially apply in addition to (and potentially take precedence over) the requirements of BS 7671 (if Reg Group 511 is invoked for conformity if the preference in 533.1.201 for BS 1363 socket-outlets is not taken up).

What seems to be rather absurd is that adaptors (foreign to UK, but not the other way about) are included. They may be inserted into a BS 1363 socket whether the foreign socket part is shuttered or not.

Outside the scope of BS 7671.

Whilst I'd agree, I'd we didn't make provision for visitors somehow, that's an issue. BUT we have something here not found in most installations globally ... the ring final circuit.

At least requiring UK outlets on those ensures there's a suitable OCPD

Aren't these covered by BS 1363-3 & BS 8546?
I haven't read the BS8546 one. 
IMO if you squint, it maybe outside BS 7671 as gkenyon says, but it is plugged into a BS 1363  so is aligned to BS 7671.
Imo a well consider installation of foreign type sockets is safer then adaptors especially with the 'I'm not responsible' sellers like Ebay, Amazon etc. I prefer to call them eFences!

gkenyon said:

Outside the scope of BS 7671.

My apologies, my last was ambiguous. They are included in The Plugs and Sockets etc. (Safety) Regulations 1994 (rather than BS 7671).

In response to Peter69, BS 8546 covers "travel adaptors", which are excluded from the 1994 Regulations in Sch 1.