The short answer is yes. No one cares what you did in the first 12 months, only the 12 months preceding expiry counts.
Here is the long answer from LASORS
Revalidation by flying experience:-
A SEP (Land) and/or TMG class rating can be revalidated
by flying experience by producing logbook evidence to
an appropriately authorised JAR-FCL Examiner, before
the rating expiry date has passed, of the following flying
experience completed within the 12 months preceding the
rating expiry date.
12 hours
of flight time in SEP or TMG aircraft as
appropriate to include;
i.
6 hours as pilot-in-command;
ii.
12 take-offs and landings;
iii. a training flight of at least
1 hour’s duration with
a FI(A) or CRI(A)* who must countersign the
appropriate logbook entry (see full details below).
... This training flight may be replaced by any other aeroplane
proficiency check or skill test for an instrument, class or
type rating (as defined by JAR-FCL) with a JAA qualified
Examiner, or by a flight test for the issue/revalidation or
renewal of a UK IMC rating.
• If revalidating by flying experience, and providing
the examiner signs the Certificate of Revalidation
page within the 3 months prior to the rating expiry,
the validity of the revalidated rating will be calculated
from the date of expiry of the preceding rating.