I think it may be cheaper to ship my car across the Atlantic, get it serviced, then bring it back to the UK.
From an Inspection II quote from my local dealer - all prices converted to US$ at current rates:
Spark Plugs $13.81. each.
Mobil 1: $22.98/litre $24.28/quart
Labo(u)r: $182/hour (it's $267/hour in Central London)
Total cost is $712.