So.  After repairing old wires etc I now have headlights, sidelight and indicators! 
However, main beam -  when switching - low to high works fine but won't toggle back to low beam. 
Where do I start? Relay? Dodgy earth? Any help gratefully received

you may have the live feed on the main beam terminal and beam on the live or low beam one, does the headlamp main beam flash work with ignition on

Wrongly connected to wrong terminals, ok, makes sense

No.  No flash with ignition on. 
How do I identify terminal numbers
5 pin relay, no numbers only a schematic on side

It's this one
Checking wires I seem to have it right

30 is a ignition switched live auxiliary a black and yellow wire. S earth through the micro switch to change the lights over dip/ main.

pull the wires off and leave 56 from light switch, 30 from aux or bridge and S connected, the relay should toggle between the two functions easily checked with a meter or bulb on pins 56 a and b new relays have been known to be faulty.

Thanks.  I'll give it a go.
Suspecting faulty as its ancient and not clicking at all now.
Thanks for your help.   
It'll be over in Evesham soon I hope.

we are easy to find not sure if there is a headlamp relay in the shed.

That's why I always just fit a foot dipswitch, to keep things simple. The only relay of sorts on any of my builds is the flasher unit.

This relay is to the best of my knowledge unique to VW and was taken up by thousands of guys who`s motors like mgb, midget etc etc had no headlamp flashing facility.

The "S" terminal is crucial. It is a negative lead, ie ground\earth. When connected correctly with a good connection to earth via the column switch it toggles dip to main beam and back using the column switch lever arm. A quick pull towards you to toggle. For Headlight Flash you pull back and hold back for a short period. Take care in this circumstance because the head flash brings all four bulb filaments on at the same time. That is to say both dip beam plus both main beam filaments at the same time. (Measured 17 amps on my buggy in this mode). 

Thanks for all your help. 
Sorted !!!  Relay was shot.  Got a new one and hey presto!   
Really appreciate your input team. 

i   have a 1964 buggy   i am having    the same problems as above      sidelamps and headlamps work correctly on the vw pull out switch    main beam is on a seperate  dash  switch   soon as i activate   full beam   it works perfectly but   as i try to    knock main beam off   it   knocks  headlamps of and leaves full beam on     but if i activate   the  main beam switch  twice it works correctly,     it has a new   headlamp relay      but    its   just showing  the  same symptons as it did with the old relay      anyone any  ideas   

the dip/ main switch is just a touch contact not a on /off switch as it is a latching relay triggered by one quick touch of the contact on it.

is the original vw  floor  mounted     contact not   a switch  as well  ,    hows the best way to   fix this 

problem is a buggy can have any year parts fitted and wired in,  Thinking a floor pedal is a switch and does not use a relay to do dip/ main although not played with one for many many years.

Floor mounted dip switch did not utilise a relay in my early beetles. Was a simple on off switch.

Much preferred is the change to the 5 pin relay. The original silver relays are all but bullet proof. The black repro units are just not in the same league but that is the world now.

As snoopy says the relay simply toggles between main and dip beams with the added function of being able to "flash" your headlights but this brings all 4 bulb filaments into action. That is both main beam and both dip beams illuminate.

Look at the 5 pin relay..... Terminal "S" is the key to switching between high and low beams. It is a ground contact. NEGATIVE that is.
On the relay diagram, in this thread, it indicates a brown wire from dimmer switch. This wire is the negative and you only have a dimmer if you have the dash mounted switch with integral dimmer. You may simply have a wire from the column switch. Usually black on repro but this is not always the case. Keith makes the point that you could have any version of switch on your buggy and boy have I learned this the hard, expensive way.   What is ultra important is that you have an excellent point of contact to earth/ground the system for switch and both headlights.

I know how confusing this all is to someone just delving into electrics but it really isn`t magic. Can you take a picture of your relay from the pin end just to be certain of what you have. Also of the switch you have indicating the wire colours. From this I will attempt to draw out and post what should go where if I can. Have a great xmas.