Light aircraft class rating in an ATPL
 

Can somebody please advise:

I have a valid UK ATPL. The ratings have expired but the licence is valid - I'm currently flying on another country's ATPL.

I now want to get a light a/c class rating in my UK ATPL. Is this possible with no valid type ratings?

To renew an expired SEP class rating only involves an LPC with an FE or CRE. It should be pretty straightforward (see LASORS if it's been expired for more than 5 years).
If you have a similar class rating on another authorities ATPL, then that also can be used to exercise privileges on a G reg'd SEP.

No, I don't have and never have had a class rating in my ATPL. I want to get one. But my licence (ATPL) although still valid, has no valid type ratings. So with this in mind, can I still get a class rating?

Extract from LASORS 2008:

F1.2 REQUIREMENTS FOR THE ADDITION
OF AN SEP (LAND) CLASS RATING
For rating issue you must:-
a. Provide evidence of having completed an approved
course of training in accordance with JAR-FCL for
the purposes of the rating.
b. Pass a class rating skill test (LST) conducted by a
JAR authorised Class Rating Examiner (CRE) or
Flight Examiner (FE).
c. Pass a theoretical knowledge exam (oral as part of
the LST).
The class rating course, including theoretical knowledge
shall be completed within the 6 months preceding the
skill test. Each applicable item of the skill test shall be
satisfactorily completed within the 6 months immediately
preceding the date of receipt of the application for the
rating.

I don't have the detail of what subpara "a" will mean, but the answer to your question seems to be: yes, you can. Perhaps best to get advice from a local club who could provide whatever training is needed.

I'll try one of the clubs next time I'm in the UK

Thanks for that!