Blimey dude lots of questions..... but we've all asked lots and some continue to ask lots... normally mine are stupid...
Right then. Bags.
Try
www.jafrum.com They are cheap, cheaper than anywhere I've seen in the UK and even if you pay customs on arrival, they are still cheap. Never seen a bad word said against them. I have a sissy bag from them I used to use for work (I took the bar off...) and I used to abuse it. I could still use it now.
Try
Custom Cruisers in Derbyshire. Never dealt with them, but the prices are what you pay..there's no customs to add when they arrive.
Keep an eye on eBay.
There are others.... I'll have a think about it.