kitchen tap replacement

[H8diy]

We bought a Gatun monoblock kitchen tap from B&Q. However, when we looked at the old one we couldn't figure how to disassemble it. We can see the difficult to get at "nut" at the rear but there seems to be a "plate" that looks like it holds the tap in place.
My son, who is far better at diy than me, is convinced that the tap is permanently attached to the entire sink top.
Please, what is this "plate"?
What is it for?
Is it possible, or likely, that the tap is "welded" to the sink top?

I am attaching some, rather poor, photo's my son took of the underside of the sink, hopefully, showing the mysterious "plate". Sorry but this is really the best we quality we could get.

Please see three (3) images in my "Kitchen tap" folder.

Kitchen tap -3

• H8diy
• 24 Sep 2013
• 1

Kitchen tap -2

• H8diy
• 24 Sep 2013
• 1

Kitchen tap -1

• H8diy
• 24 Sep 2013
• 1

 

[Madrab]

I think that plate is just a strengthening/locating plate that's came with the old tap. The new ones are round instead of square. I wouldn't think that the tap is permanently welded to it. What you may find though, given the plate looks like it's rusted, is that the threaded bar may have become rusted against the plate and the plate against the steel so may be a bit of a bug*er to get loose
Remove the nut, take out the pipe tails by unscrewing and twist the old tap, it should move.

 

[ivixor]

Undo the nut with a socket on an extension bar. The rusty plate will then fall down and the tap will come out the top.

http://www.bhl.co.uk/images/tagged/...ssance Monobloc Sink Mixer Spares Drawing.JPG

The rusty plate is labelled 7 above.