HMRC releases annual experimental statistics that subdivide the existing Regional Trade in Goods Statistics into smaller UK geographic areas. The latest data relates to 2020 and is available at ITL2 (Somerset grouped with Dorset) and ITL3 (Somerset only) geographical levels. Trade data is taken directly from HMRC.
This data shows that in 2020 the volume and/or value of trade with non-EU countries exceeded that with countries within the EU. Whilst exports to EU member countries equated to c£480m, exports to non-EU countries equated to c£876m. The value of imports across EUI and non-EU were more broadly comparable. Overall, in terms of goods (the data not including service trade) there was an overall ‘trade deficit’ (some care needs to be taken in terms of allocation of trade to smaller geographies) with the EU. In comparison, the data suggests a small ‘trade surplus’ with non-EU countries.
 International Territorial Levels
Source: UK regional trade in goods statistics disaggregated by smaller geographical areas – GOV.UK (www.gov.uk)