Yes, I don't remember the details of the issues the RAF Harriers faced, but they wouldn't have been helped by their relatively intense usage rate versus the US Marines' fleet. However, the largely composite structure (made mostly in the USA, I believe) is fairly easy to look after and repair if you have the facilities of the largest military support infrastructure in the world! To all intents and purposes, the AV8B (Harrier GR5/7/9) is an American, not British, product.