Greggs is seeing quite a lot of auction activity today too (despite being on the SETMM segment - which kinda confused me, but still, I’m easily confused)
If you just happen to execute during the seconds the order book is not executing automatic orders because an auction uncrossing is taking place you see some (quite minor-ish) changes in price.
I’ve put a few orders through Freetrade and not really had an issue - the auction uncrossing is fine and perfectly legit. They seem to report out as executed on the LSE. I’ve shoved a few through other brokers and can see they get “systematically internalised”… which is a horrible way of saying “kinda made up based on the best prices we had a few seconds ago and what we as market makers are prepared to suck up right this second”… (but also perfectly legit in most case)
I also saw the order book for Gregss come to a halt this morning for quite a few minutes… which normally means a circuit breaker triggered (which it doesn’t appear to ) or an announcement (which there hasn’t been)… or… I dunno.
Long story short : All is well. Your orders went via RSP which categorically makes them
“best execution” as per my experience with clients claiming otherwise (admittedly over a decade ago!)