Suggest you also contact for advice Delta Conversions that markets Nordelettronica equipment in the UK
https://deltaconversions.com/
I think the TE43 charger had an output around 16A, but I notice that Delta Conversions is currently offering the NE287 21A charger for £110 and stating that this is "Designed to replace any past Nordelettronica charger”.
https://deltaconversions.com/shop?olsPage=products%2Fne287-battery-charger-21-amp
As your expired TE43 charger is 15 years old, although repair might be possible, replacement would make much better sense.
Whatever charger you get, some wiring modiications may be needed - but choosing another Nordelettronica charger might minimise that potential requirement.