Ah, worth having a look over the execution policy
Once the order has triggered, it is not possible to cancel.Buy Limit Orders and Sell Limit Orders will only execute at or better than the Limit Price set by you.
Stop Loss Orders will not necessarily execute at the Stop Price set by you and will often execute at a lower price, due to the inherent nature of moving markets and the price at which our market counterparties or other market participants available to us are willing to buy at that time.If the observed market price reaches the Limit Price or Stop Price you set, it will not always mean that your order will be executed, for example, due to differences between price data and the prices at which our market counterparties or other market participants available to us are willing to buy or sell.
You should be conscious to accept the risk associated with this type of instruction. Freetrade will not be liable for losses incurred due to the selection of the Limit or Stop Loss Order types, save any assessment made by us that we have fallen short of our best execution obligations.
Your order, regardless of type, will only be carried out if all of the required shares are available to be purchased in the market, i.e. your order will never be partially filled. This is known as ‘Fill or Kill’. Catchy name.
I’ve a thread about the boring documents Seriously, Read the Execution Policy and the T&Cs