Nicholls & Anor v Mapfre Espana Compania de Seguros y Reaseguros SA  EWHC 1031 (KB) yet again discusses the evidence and procedure carve-out in Rome II and its relationship with A15 Rome II ‘scope of the law applicable’. In the absence of a possibility to refer to the CJEU, a Court of Appeal intervention might be useful.
Pandya v Intersalonika  EWHC 273 (QB) held that proceedings were time-barred per Greek law (lex causae), where the claim form was issued in the E&W courts before expiry of Greek limitation period, but was not served until after that expiry. A narrow reading of the A1.3 carve-out was confirmed in Johnson v Berentzen  EWHC 1042 (QB)) and in Bravo & Ors v Amerisur Resources Ltd (Re The Amerisur plc Putumayo Group Litigation)  EWHC 122 (KB).
In Duffy v Achmea  EWHC 3341 (QB) it was held that interim payments are within the evidence & procedure exception; in Troke v Amgen  EWHC 2976 (QB) interest payments, ‘because they are discretionary under Spanish law (the lex causae)’, were held to fall under the A1.3 exclusion. Sedgwick v Mapfre concluded the same (albeit on better reasoning IMHO) That seems to also have been the approach in Woodward -v- Mapfre, unreported but referenced in current judgment by Spencer J.
Eventually however the judge does not follow Troke or Sedgwick, holding  that the recovery of interest provided for by Spanish law under Article 20 of the Spanish Insurance Act is, pursuant to Rome II and as a matter of European law, substantive, not procedural. In essence, the relevant foreign law rate of interest is said to be a matter of clear relevance to the remedy (financial compensation) to which the claimant is entitled, being intrinsically connected or linked to the award of financial compensation.
His reference (1) to the suggestion that A15′ applicable law provisions needs to be construed widely and A1’s carve outs narrowly, is wrong in my opinion.  He clearly suggests he might have referred to the CJEU had that been possible (although I do not necessarily agree that the CJEU would then have looked for a ius commune approach across the EU).
Even though he finds fault with the application of the rules by the lower courts, his calculation of awards are the same and the appeal fails.
EU Private International Law, 3rd ed. 2021, Heading 4.8.