Neil,
Lots of options here! To be honest if you want shiny I'd go with polished stainless steel as they really are easy to look after and they often appear for sale on this site as some don't like full length bumpers preferring either over riders or the naked look! I like bumpers so I have full length SS front and rear. Lorne is absolutely correct in that they only protect for the lightest of contact and the rear mounting brackets can easily contact the rear panel if flexed a little too hard!
If yours are anodised well that'll be quite a lot of work and then on going maintenance to keep them like it. Aluminium is tricky to chrome and doesn't stay fixed as well as on steel and isn't cheap. There is a new system around now that looks like a chromed finish, its called silvering and they claim they can silver anything and its cheap! Have a google and see what they say. I have seen it done and it takes minutes and they claim high levels of durability too!
Stainless new with the mounting bracketry are probably about £1300 each so second hand is the way to go and you should pick them up for £5-600 in good condition with the mounting hardware. To be honest its all about the look all options provide, what you like your Morgan to look like. I'm getting on a bit now and like the full bumper look as its a look of my time but if I was ordering now I'd probably go for over riders, possibly on the rear, the simple bumper bar/rack combination.
Knowledge is power and I think you are now getting most of the answers you'll need to reach your final decision! good lock with your endeavour.
