Comply with 14 CFR 61.56 'Flight review'
and, if necessary, with 14 CFR 61.57
'Recent flight experience: Pilot in command.' These differ marginally from those established under JAR-FCL and, in the case of operations carried out under a US restricted private pilot certificate, will need to be simultaneously satisfied where applicable.
61.56 requires a revision of (in your case an initial familiarisation with) Part 91
'General operating and Flight rules.' You'll need to carefully cross-check the US regulations under Part 91 against the Rules of the Air / Air Navigation Order and revise the relevant section(s) of the UK ANO Sched. 8, including extra-territorial provisions of the Order. See Home - Statute Law Database
for UK Order & UK Regulations.
Owing to peculiarities of the legal language currently employed in the governing US regulations the state of issue of the JAR-FCL medical certificate must match the SoI of the licence. If you intend to undertake international flights under the privileges of the US restricted PPC the FCC will expect you to hold a restricted radio operator's permit (separate registration with FCC required - fee about $60, takes a week.) UK FRTOL puts you in a higher category vis-a-vis satisfying relevant Radio Regulations annexed to International Telecommunications Convention so I wouldn't be too excited about jumping through FCC's hoops.
Familiarity with US VFR charting practices, flight plan differences, met. services, transponder conspicuity codes, uncontrolled aerodrome joining/exiting procedures, approach/runway lighting systems, ad nauseum is contained in the FAR|AIM publication and should be covered during the flight review.
Enjoy the free crew cars.