Front spark plug turns forever?

Not sure what's going on but my K4 pointy will turn over but won't catch, so having neglected them for a couple of years I thought i would give new sparks a go.
The trouble is I can't seem to shift the front spark, I have the OEM tool kit and also a halfords that both appear to slip down and fit, but the sockets just turn and don't feel like they are turning anything, for a long time, and I have tried both directions.

Shining a torch down (have the front cowl and rad removed) I can see what looks like like the large nut, but it looks bigger than the OEM plug socket with little between it and the engine block?

Anyone else have this experience, am I missing something obvious?

Cheers

Stage 1:As you drop the spark plug spanner down teh hole it'll hit the plug,
Stage 2: Turn the spanner 5/10 degrees in either direction and it should drop down a couple of millimeters further (this is when the hex of the socket and the hex of the plug nut align).
Stage 3: Gently depress the spanner a little further, this should be where the spark plug node sits into the little rubber grommit inside the spanner. Then turn anti clockwise and the plugs should come out.

Try it with one of the plugs your intending on using as replacements and you'll see what I mean abotu the 3 stages above.

Thats all I can offer, assuming you have the correct size spanner for the job.

Thanks Owenski, I have kind of tried all that though not so methodically, I will give it another go using your steps.

failing that and asuming the spanner is the correct size, the nut must have come undone from the plug,= fubar

Have you done the back cylinder yet?

Have you taken the rear pug out?

Does it look like it has the same size hex as the one in the front?

[punyXpress]

Measure how far down the hole the hexagon is = A
Measure how far down the hole the socket goes = B
If A > B+10mm, the socket isn't going far enough down the thickness of the socket wall MAY be too great ( The plug spanner in the toolkit is probably the only one they give you that's any use )
If the socket engages the hexagon, you are deep in the brown stuff, but you dont need me to tell you that!

[_Stretchie_]

Alright mate, put your location in your personal info there might be a local that can come and help

Blimey a lot of helpful replies, thanks all.

_Stretchie_ I'm down in north London, will put it in my info.

Kerby & RenascenceBlue_ I haven't had the rear out, that;s another headache with a chewed hex seat-panel cover-nut, but that i can remedy with a hammer and a larger hex I think

punyXpress - I've used both my Halfords and the suzuki sockets to change this plug before so I'm confident it fits. I took a pic just now to see what's going on, and it may well be the brown stuff I'm in....

It appears there is no thread, or it's so rotted it's no longer visible? If that's it at the bottom it's too thin a distance between it and the wall to get even the suzuki socket on.

I tried Owenski's method, got the rad clear and gave it a good thunk down into the hole, good jiggle but it didn't catch on anything.

I take it even if I got a grip on the porcelain it would snap well before turning? Any special tools out there for my plight?

Looks like the hex nut has disintegrated, can you not stick some wd40 down there to soak in, obviously not so much that it goes beyond the spark plug then try turning it.

I haven't changed one before but if you have no other option is there a possibility of trying to break the hex nut (seems to be rusted and half missin anyway... No?). I would try with a long sharp flat headed screw driver and hit the hex nut and try to break it in half, the pressure is between that and the threads, once that is broken perhaps it would release the plug and you could turn it?