Suspension help needed

Hello guys, just need a little help I been undersealing my GTI, when I came a crossed a split rubber bush that sits on top of the suspension shaft in the front , below the suspension mount but under the arch,just between the spring and the shaft of the suspension, lol sorry for the confusion, I don't know the exact name for it, so needed help on the following 

1. Exact name 

2. How would I replace it 

Thanks in advance all help appriciated, lol need to know the name 

vwheritage has a good diagram:
http://www.vwheritage.com/vw_parts_Front-Suspension_act_page.render_pageID_1101.htm

probably looking for the bump stop?

Lol spot on ned, I think that's it bump stop, so basically do I have to take the suspension arm out undo the top suspention mount ( being carefull with the spring) and replace the bump stop and assemble everything back, or is there more to it cheers guys 

I've never done this before but I read somewhere that you may be able to undo the top mount nuts and lower the strut down enough to be able to take the top mount off and replace what you need to replace, without taking the whole suspension strut assembly off completely.
not sure if that's possible though but this guide might be useful:
http://vwgolfmk1.org.uk/forum/index.php?page=topicview&id=how-to_2%2Freplace-front
 

Thanks Ned, it seems a good guide with pictures, easy to follow, thanks again mate appriciate the help 

The bump stop caps do they go down first then the bump stops or are the caps ment to go over then bump stops, just because on my one the bump stops are visible and the cap is at the bottom of the spring, sorry if I'm making this confusing just need a little help making sure it bes done  right 

You need to buy spring compressers to do this job as you have to remove the spring 20ish £ should buy you some.
If the plastic dust cover is at the bottom of the shock it's either broken of come lose from the bump stop.
They should look like this when the car is rasied.


If they look like this then either they have come out of the grove in the bump stop or the bump stop is broken into bits.


You can see the grove in the bump stop in this picture. Mine broke because the shock was worn out so need replacing.


Follow the guide in the other link to remove the front strut and check the shock while its all off the car and the spring has been removed, fit a new set of top mounts if the top metal bit has started to move up from the rubber, its where the nut at the top is.  You will also need to get the camber checked once everything is back on the car.

Thanks mark1gls, mine has come lose, thanks again guys appreciate all the help