Yes they can as long as they apply to class ratings and/or non-EASA aircraft types, but if they are for EASA aircraft types.
Here is some background, which some may know and others may not - plus some predictions:
In the beginning there were UK national licences that could carry ratings for any aircraft on the UK register.
Then JAR-FCL came along. These licences were still under national law and were added to the Air Navigation Order. Being national these could still include any aircraft type or class, including microlights etc. But some of the rules for JAR-FCL licences were different and they had the privileges of being valid for aircraft registered in any JAA Member State.
When EASA and Part-FCL arrived that all changed. Part-FCL licences are valid under European law and can only hold ratings for EASA aircraft. UK national licences remained valid under the ANO but only for non-EASA aircraft (formerly called Annex II, now Annex I due to a renumbering in the EASA regulation). JAR-FCL licences and rules were removed from the ANO leaving only the original national licences but with a prohibition on including EASA types/ratings in those national licences.
To try to prevent licences being issued with the wrong ratings, the CAA's computer software was amended to produce national licences and European Part-FCL with inbuilt rules that ensured that only ratings included in Part-FCL went on Part-FCL licences and only ANO ratings went on UK national licences. These cannot be overridden. And that is how it remains today as we are still in the EU.
So today, the CAA can't put anything associated with an EASA type on a national licence - computer says 'no'.
I am guessing that the machine and/or the staff see your night rating and IR as being tied to the SK92 and so not eligible to go on the UK licence.
So what about the B word?
The CAA's plan for Brexit is that they will copy all of the EU aviation regulations into UK national law, but alongside the ANO.
The draft legislation to do this has already been published. It is hard to read as it is just the edits, but what it appears to do is adopt all of the European texts but replacing: EASA with CAA, EASA aircraft with Part 21 aircraft; and non-EASA aircraft with non-Part 21 aircraft.
So if the UK leaves the EASA system the CAA will then issue UK-FCL licences in place of Part-FCL licences. The UK-FCL licences will have the ratings for Part 21 (EASA) aircraft and the old national licences will continue as now with just the ratings for non-Part 21 (non-EASA) aircraft types.
This will mean minimum change for licence holders and the CAA.
So, in years to come will they change it so the UK national licence can hold any rating?
I doubt it, because it is not essential and would cost a lot of time and money, not least in writing new software.
And my prediction is that the CAA is going to become very short of money very soon as other UK airlines follow Easyjet's lead and become European to protect their access to European routes. (It has been reported in the general media that Easyjet is moving it's AOC to Austria; that they have transferred 130 aircraft to the Austrian register; and over 3000 of their pilots now have Austrian issued Part-FCL licences). As I recall about 50% of the CAA's income is from the charges paid by UK airlines. I note that Thomson rebranded as TUI awhile ago (the name of their german parent company) and British Airways is owned by IAG who also own Iberia. So British Airways could just become 'BA' (as British Aerospace became BAES) and cut itself free from the UK and the CAA. I think that may happen whether or not Brexit goes ahead given that the government is incapable of giving industry any certainty for future planning.
So my prediction is that, within a few years of Brexit, there won't be any major UK commercial operators, even if we eventually settle on staying in the EASA system. Those companies will still be here but they will be European companies regulated by EASA and the remaining EU Member States. The CAA will be left with UK airspace, ATC, aerodromes and UK non-Part 21 (non-EASA type) aircraft - i.e. homebuilt aircraft, ex-military, microlights, gyroplanes and drones.
I understand this is called "taking back control".