Thanks poulan for joining the community and all the fun we've all been having!  If you need more help we're here!

OK thanks I will bare this in mind. Appreciate everyone's quick replies here getting a newbie up and running.

What your looking for is each time you hit z-home.  You want the end switch hitting that screw.  It should then bounce back 5mm's before returning to home.  Repetier will then know where home is.  You then tweak the z-screw till your nozzle height is where you want it hitting home button each time you adjust the screw.

As long as it works and you still have range in the screw for adjusting the squish of your first layer, you should be good then.

It does seem a bit odd ward, since it was crashing after snugging up the carriage.
Would you be able to post a couple pictures poulan?  A shot of the z screw, then clearance when you home it of the bed and nozzle?

+1 that's all I was saying is something seems off.  It always hard to trouble shoot from written description.  A picture is worth a thousand words.

It does seem a bit odd ward, since it was crashing after snugging up the carriage.
Would you be able to post a couple pictures poulan?  A shot of the z screw, then clearance when you home it of the bed and nozzle?

This is the first time I'm levelling it.

I've set the x, y and z at 0 in manual controls of repetier (this is what I interpret home to be) and it has left me with around 4.5mm of space between bed and nozzle. Moving the Z dial at the back lowers the pin but it never reaches the microswitch which is why I'm getting stuck.

But this is what he said.

I wouldn't worry about what the numbers repetier is giving you.  Those are only based on where the end stop was last triggered.

It sounds like you're getting it figured out, at least in the right direction.

So I've put the bed up as high as it can go and assumed this is the home position which is Z = - 7.16 and set the Z to top out at that level. Good so far or should I be having repetier at Z = 0.00 and tune to that?

From there I plan to level the bed.

I've set the x, y and z at 0 in manual controls of repetier (this is what I interpret home to be) and it has left me with around 4.5mm of space between bed and nozzle. Moving the Z dial at the back lowers the pin but it never reaches the microswitch which is why I'm getting stuck.

Use Repetier and bring the bed down below the nozzle with the controls in manual mode.
Use the controls again to move the nozzle over the bed just a little bit so you can see the clearance between the two.
Then bring up the bed in small increments until you have the smallest gap you are comfortable with.
Now you can adjust the z stop thumb screw in the back until you hear the switch click.  That gives you your starting point.

Have you leveled your bed before?