Applying discounts for multiple purchase

[seanathome]

Would like to set up a promotion where the purchase of 3 particular items at £4 each gives a £2 discount i.e. 3 for £10
Have created a rule called multibuy selected the menu item name & put 3 in the quantity field. Then creatred an action called multibuy.
Tried this combination with update last ticket item price tag & update ticket item price tag, both with price tag £1. Then tried add ticket discount using 10%.
No joy with this, so filled in terminal name & department name fields in rules, but still no joy.
Now with my limited knowledge, I'm stuck. Would appreciate any help to guide me through this.

[seanathome]

Further experimentation to improve my knowledge.
Changed the quantity in rules to 1. This now applies the 10% discount to the ticket but doesn't work if I try to change the item price.
Also found that if I select 3 x item the 10% discount works with the quantity in rules set to 3. That doesn't help if the 3 items are added 1 at a time.

I'm a step closer, but still not there yet

[seanathome]

This is getting quite frustrating now.
To make sure I'm doing each step right I've tried to update the price when just 1 item is selected. I can get 'add ticket discount', 'add ticket item', 'gift last ticket item' & 'update ticket item tag' to work no problem.

Using 'update last ticket item price tag' & 'update ticket item price tag' does nothing. Have tried 1.00, 1, 5, £1, £1.00 in price tag parameter.
What am I doing wrong?

[emre]

If you didn't do so create a new price definition and enter a short price tag as you like (For example dsc. We prefer short names here because it will appear next to prices. )
When you enter price list editor you'll see a new column added there. Enter discounted prices there.
When you apply this price tag to an item it's price will change to the price tagged as dsc.

[seanathome]

Thankyou. 
Thats been driving me nuts.
Sorted now.