Glad you're safely on the hard shoulder, it could have been a lot worse
Yes, cast arms are a straight swap. Although the bushes are the same size, the ones for a diesel are of a more robust construction, to deal with the greater engine weight. Depending on your annual mileage, you may get away with arms recovered from an end-of-life petrol car if the balljoints are good. New cast arms aren't as widely available as they used to be. Meyle are now the brand that WOM uses. Maybe talk to them about the correct part number for the bush?