Help fitting bar shower - shower pl8

[jammmy]

Hi, I have recently had a loft conversion and on the 1st fix the plumbers installed a shower plate called the showerpl8. This has a plate behind the wall and leave a piece of pipe coming out that you attach a male coupling to after tiling. (http://www.ebay.co.uk/itm/MARFLOW-S...LVE-FIXING-150mm-FAST-FIX-PLATE-/221952395934)
Because I enjoy a bit of diy and to save a few quid, I said I would fit the toilet sink and shower in. I have done it before but always used the stuff that came from grohe with wall elbows instead of a plate.
Anyway I have a bit of a problem in that the coupling doesn't appear to be long enough. Well it doesn't have enough thread on it for me to fully tighten the nut, have enough thread to screw the cover to ( on the right of the pic) and get a thin spanner in.
I would be grateful for any advice. As you can see from the pic, the grohe part has a bit more thread on it.

As it's past 5 I wont be able to call the manafacturers of the plate until tomorrow but was wondering what I could do?
I was thinking of packing it with an extra fibre washer or 2 or maybe just trying to seal it with ptfe and not pushing it all the way home, though this could be tricky as it is hexagonal.
Would either of these be suitable so I can get maybe another 3mm of thread?

Thanks for any advice.

 

[Baz100]

At what stage is the backplate installed to (i.e. has the copper tube already been cut to size?) If the copper has been cut an the connector compression fittings tightened then the depth is already set. How many FULL turns can you get on the nut? I believe the nut you are referring to on the shower is a face-seal (with the nex nut being captive), so PTFE wont work. Your idea of multiple face seals has been done before using 2 rubber seals, not sure I would go any more. Just need to make sure you have a good loaf of full turns on the nut.

If the conical cover goes between the hex fitting and the wall, what I have done before to buy myself a few mm, is to sit it on a sanding disk to take off 3-4 mm of the plate at the back,.

 

[Madrab]

Sounds like the couplers and tails out of the wall weren't made long enough to take the covers and shower, only option is to get shallower covers or cut the base of those ones as Baz mentions. If you're good with an angle grinder, 1mm cutting disk and mask the cut. Job done.

 

[JimCrow]

Drill a 12mm hole in the centre of a 2 pence and put a washer either side of it,
you may need to file the rim of the coin down slightly to fit in the 3/4" nut.

 

[jammmy]

Thanks for the advice, I spoke to the manufacturer today and they said no one has ever had this problem before. Which leads me to think I'm doing something very wrong but I still can't work it out without using one of the methods suggested here.
After fully tightening the nut into the shower I only had about 5mm to get a spanner and the cover on and the cover took all 5mm to bite on the thread.

I went to see the people I bought the shower from today and they kindly let me swap it for a different model that should be better. I'll try it tomorrow.

Thanks again.

 

[Madrab]

The pipe tails aren't long enough to accomidate the covers and then leave enough of the 3/4" male fitting to then screw the shower onto. Just a case of incorrect dimensions. Going by looking at the kit, can't you remove the tails fitted into that bracket and replace with new, longer pieces?

Alternatively, get a pair of these, can't go wrong -