I checked LASORS, seems to suggest that as long as my LPC is conducted within 5 years of my last LPC expiry date, an LPC would be the only check necessary.
I think you may be confusing two issues.
An LPC is only valid for 1 year as previously stated. If you
revalidate (i.e. do an LPC up to 3 months before the due date), your LPC will now be valid for another 12 months from the date it would have been due. In other words, you could go for 15 months between LPCs.
If you go one day beyond the due date, but not more than 5 years, you will now need to
renew your rating. You still have to do an LPC (as you would have to have done so for a revalidation) plus any training that your organisation requires.
If your rating lapses by 5 years or more, you have to undergo training "as required", pass an LPC but this time, the examiner cannot make an entry onto your licence. The paperwork gets sent off to the CAA who will, in effect, reissue the rating (at a cost, of course).
Hope this is clearer.