Stunted pepper plants

Three are 3 in the soil next to what Americans would call a "greenhouse"? Which way does the wall face? How was the soil prepared? Here, 18 lbs of aged chicken manure/ 100 sq. ft. (8.18 kg/9.29 sq. m.). What is the soil, clay, loam, sandy?

It could just be a matter of a "watched pot". Since they don't sound like they are in distress, put a tape to them and measure them. Then tell us how old they are, what kind and how much fertilizer, what have temperatures there been like since the peppers were planted, how much sun do they get, what is there soil moisture like, how big are the pots, and what do you mean by "may have been over watered?" Since you describe them as bushy, apparently they are expanding spherically and not linearly, which would be more dramatic.

these are all good questions and things that need to be considered...

Redskin plants are supposed to stay small, they're bred for containers. By the end of the season, mine hadn't gotten more than a foot tall.

Apache is another dwarf, and won't get too tall. There are so many different kinds of cayennes, it's impossible to figure what is the correct height of the plant.

How are they doing now?

Penelope