The first major study of pewter ingots is Beagrie (1989) expanded by Lee (2009). Ingots, of all types, are datable to the 1st-4th century AD and occur across the south of Britain, mostly on rural sites.
Distribution
It is perhaps unsurprising that tin ingots are found in the southwest, the hub of tin mining in the UK, and that tin/lead alloys occur mostly in London and Cambridgeshire, areas with evidence for pewter export and recycling.
Forms
Although there are variations in ingot type, for example 'bar' ingots and plano convex ingots. However discussion of these differences falls outside the scope of this section at present.
Chronology
the dates for known finds of tin and pewter - tin and lead - ingots is mostly 4th century AD. However the presence of one probably 1st century AD ingot from Cornwall would fit well the evidence we have for tin mining in the area.
References
Beagrie, N. 1989. The Romano-British pewter industry. Britannia, 20, 213-244.
Lee, R. 2009. The Production, Use and Disposal of Romano-British Pewter Tableware. Oxford: Archaeopress.