Urban art in Staines

The inscription says it's in the style of a Samian pot made by Cornutus AD 125 found on the site. "Giorgio Fantelli facit MMII."

I wonder how many people have seen this. It's on the wall of an anonymous office block away from the shopping centre. Staines is an ancient town, but although there is a small museum, there's very little publicity about its past. What else is under that office block?