Manifold replacement
 

I have 5 year old SX18. Last year I replaced the external bellows and have just been told by the service engineer that the manifold is rusting and needs replacing before salt water gets in to it.
I have been quoted the following in Spanish (based near Barcelona)

1 Colector 860235A03 417,46 presume this is the main manifold part
1 Codo 12076A2 252,62 this is the 'elbow'
1 Junta 27-997772 4,89 these are some sundry parts
1 Junta 27-815528 24,28

700 euros just for parts sounds expensive to me. What should it cost? Has anyone else done this and what did it cost? I don't mind paying if it's reasonable, I just don't want to be ripped off. To be honest they have done a good job so far and not overcharged for antifouling and service.