Green Holkham-style owl mug, probably Secla Portugal

Hello. Clearing a neighbour's house and cam across this very cool coffee or tea mug. It's a dark green glaze with a cut through integrated handle. P.2497 impressed to the bottom.  She didn't have anything fancy in her house so I suspect this is probably a mass produced item, but interested to try to get more if I can identify what it is.  Thanks in advance.

I know these to be by Holkham Pottery who is based in Norfolk (my neighbouring county), and they would normally include the Holkham Pottery printed mark. I see something printed on the base, but I cannot quite make it out. These are pretty common and are known as owl mugs that come in green, brown, blue and grey.

Thank you so much. The mark on the bottom is left over adhesive from an absent label.

I think this may be Secla Portugal who produced a similar range of these mugs