Help with some electronics please

I wonder if someone could help me understand a couple of things with regard to a circuit that I am trying to assemble. Now I know this is supposed to be a very simple basic circuit but please bear in mind I am taking my first steps and have done a tiny progress in as much as managing to assemble the kit up to a certain point. There are couple of things that now I really would appreciate some help in.

1- the Thyristor or (SCR as mentioned in this diagram
I am assuming I have connected the Anode, Gate and Cathode correctly. I get the flactuation in voltage when I shine white light on the PT. I am connecting the Gate which I am assuming is the middle pole to the resistor and then I am lost with regard to the Anode and Cathode. I see one of them to earth and also connected to the other one, so would that be the Anode?

With regard to the 2N2222 transistor I have managed to get it to work by finally finding out the correct way of fitting it, I am hoping, and now when I test the circuit with different PT of varied sensitivity I detect fluctuations in the voltage. I have managed to attach the meter on the Gate and Cathode of the SCR (which I am assuming again is the correct way and these is from where the leads should go to my flash cable that I have stripped). When I shine a white light the voltage goes down to almost 1.2V and when I cut it off it does go to between 5 and 8.8V depending on which PT I attach.

So I am assuming that I have managed to get there but now the problem is the flash doesn't fire when I attach the cables to the SCR. Am I missing something here? Is it because the PT is not getting enough light to bring it down to 0 totally and then cutting it out the flash is not getting the proper surge of voltage to fire it up? A bit lost here, so if someone could give me some hints or tips on what could be wrong here I could try again. The circuit does look straight forward and with the exception of the SCR and the N2222 transistor which gave me a bit of a headache to figure it out how to finally fit it I think I have the correct assembly.

I am off to Maplin again to see if I can get a laser light, am hoping that lack of concentrated beam of light might be affecting also so I want to get that one correct too, just in case its affecting.

One last thing, When I hold the stripped wire from the flashgun and touch the two poles of the SCR the flash does fire, its only when I have linked it and then play with the light shining on the PT that the flash doesn't fire at all. Is there something that I might be missing here too?

Thanks for all your help.
The diagram I am following is on this page under Photogate Trigger.

Amin, first lesson in electronics:-

Never assume anything, make sure. That is, you can't assume that just because the gate of a thyristor appears to be the middle pin in a drawing, that it will be the middle pin on the physical component.

You must check these things. Getting it wrong can be both costly and dangerous.

This circuit looks to be so simple that if it doesn't work, you have one of the active components connected incorrectly. If that is the case, re-wiring it correctly might not work either if it has been destroyed by your first attempt. You might have to buy one or more new components.

Firstly be VERY careful with flashguns - they can deliver a nasty shock.

I cannot see any reference to which SCR you are using. If you know it's identity, you can go to RS's website, http://uk.rs-online.com/web/ and search for the number and you will get a layout by downloading the data sheet.

Connections the SCRs and transistors vary from device to device. It is essential that you refer to the data sheets of each specific device before connecting. As has been said, above, operating a device, just once, with the wrong connections can destroy both it and some of the other active devices in the circuit.
To avoid going round in circles, start again with new active components when you are sure of the connections.
Good luck. (You don't need luck - just care! That's too smug, I know!!!!)

HI, thanks for the comments, just wanted to come and add that I have managed to work around it, thanks for your comments and help.

Amin