IMHO swap would be possible. Fiat used both engines (1.3D and 1.4 TD) in Uno. Assuming that this 1.3D is Fiat's engine. Probably you should ask Uno men? Did Fiat import diesel Unos to GB?
Sutjeska
Answer: Yes, it did, but only Uno 60D with 1.7 Diesel engine. But, as Bartpanda wrote, it's the same family as 1.4 TD. I can ask on polish Uno forum, if you want to. Maybe they know, Uno was popular in Poland.