Not sure of your budget mate, so can't really recommend any components. JBL do some fantastic gear for the money, especially their amps and their older GT4 sub.
The older model sub (the GT4) will out perform the new model (GTO1202D) in every aspect except for the fact that the newer model can be wired to show more power from an amp. But unfortunatly they can't handle that extra power (unlike the GT4) therefore that is pretty useless.
JBL GT4
JBL GT01202D
Don't be put off by the fact that it is the older model. It sounds clearer and louder than the GTO mainly because it can handle a lot more power on a daily basis. It's also cheaper.
As far as the amps go you'll be pushed to find a better amp for the money than the
JBL GTO75.4. This amp will power both the sub and the components nicely. There is no need to go with seperate amps it's just more hassle.
If you don't have a set of components in mind tell us what budget you have to work and i'm sure you'll get some good recommendations. If you can afford £90. Then you can get your hands on the best entry level components available, either the
Boston Acoustics S50 or the
Rainbow SLX230.
Hope this helps at all.