It sounds like you have a semi-concealed gas meter, meaning it's half dug into the ground, the meter box is also usually brown in these cases.

It’s now possible to install an S2 smart meter in the majority of these set-ups, as long as the engineer has a bracket on them to ensure they can fit the meter in to the space provided. When making the booking it just needs to be made clear that you have a semi concealed gas meter box.

In some cases a semi-concealed gas smart meter installation may be affected by an unusual ECV (sometimes replacing the ECV in semi-concealed boxes can be difficult due to the space). If you are worried this may be the case I would advise sending a picture of the meter box to our Support team who’ll be able to check this for you.

There’s more advice about meter issues affecting smart meter installations in our On site work guide.

And for comparison, here’s a photo of my semi-concealed gas-box with the old meter before the Smart Meter got installed.

So, apart from the fact that mine was guarded by a rat, I really can’t see why mine was acceptable for a Smart Meter and @gustavo’s was not!