Average of last 12 non zero cells

[devunow]

Hi,

I am trying to work out the average of the last 12 non zero entries of range G3:BT3. The formula is in HD3 (there is also one in HD4)

(It's to workout the average hours worked over last 12 weeks worked)

I can't seem to get it to work? It's attached below.

Anybody have any amazing ideas?

Many many thanks in advance