The other thing is that this is now a sets/mm stock. On smaller quieter stocks there is greater intraday twitchiness with sets/mm than when it was SEAQ. Greater scope for silly orders to be briefly placed at some distance from the pack and then withdrawn by any individual with market access, without any related trades being involved. More about that on a new thread soon.
Arranged stoplosses are marketed as protecting against a risk. But they also add a risk (of being easily/frequently triggered on annoyingly brief moves), so both risks need to be weighed..
I very rarely (almost never) use arranged stoplosses. But even if I frequntly did, I wouldn't do so on a stock the price and trading pattern of Tanfield.