Hi Again @J_Westlock, OK the trade data for RSAB today obtained from ADVFN illustrates the points I was trying to explain to you earlier, see below:-
The “official spread” was the same all day, see the Bid (132) & Offer (135) columns. But no trades were done at these prices. All the buys went through at 134.9 slightly under the official spread offer value. Two sells went through at 133.45 and one late in the day at 132.5 - again all slightly above the official spread bid value. Had there been ANY trades in the list at 132 or 135 exactly I would strongly suspect that those trades were done using a broker that can ONLY trade at the official spread figures.
Here is todays trade data for RAVP as well:-
As you can see the official spread figure changed at various points during the day, but the Offer figure was 135 all day and the Bid figure was 130, 132, 133 & 134 at different times. My reading of this is that ALL the trades were Buys except trades 4 & 5 that were Sells and went through at 134.5 & 134.56. Trade 9 was a large trade and they had to pay more than 135, that can happen too.
Anyway no need to experiment now, you can see how it all works right there in those examples I think.