exeng:
I did exactly this. I went back to single-engines after an absence of over 20 years. I bought a PA-28 and found a friendly instructor to ease me back into PPL thinking. I did five hours dual (which I thought was about right) while things came flooding back and then did a check ride with the local examiner.
The CAA issued a separate "Rating-Certificate of Revalidation" form endorsed "SEP (land)" which I kept in my JAR ATPL as a separate page.