Thanks everyone for your input! Interesting re the stim cycles having something to do with it. Jury is still out by the looks of it.

My scan went great, all normal, baby must have just been curling up tight when measured, as it around the 50th%ile for weight ( 2.7kg) and all normal so full steam ahead there. Looked really cute with chubby cheeks!

Special thanks to Traveller for coming and holding my hand through the scan