Re-potting chilli plants

[Nat22]

So do they live in the garden in the summer?

The green stuff will be algae and may be due to wet conditions.

It's getting a bit late in the season to be re-potting, but you could scrape off the top surface of the compost and top dress with fresh.

Yes they are outdoors all summer. I'll try scraping the surface for now then and re-pot in the spring.

[The Large One]

i'd pot them on, no real issues as long as you water them before and after
a sudden lot of room for the roots to stretch their legs will be welcome coming to the end of the season and may prolong fruiting a bit

[Canny Grower]

This looks like 'loco'. The fruits start out purple and turn red when ripe. I ended up with a great assortment of chillies this year and this is one of them. I was quite surprised to see the fruits as I'd never seen a purple chilli before.
I'm pleased to hear you've kept yours over winter as I hope to do the same. I believe this plant can grow to quite a size.

[Nat22]

The colours on this plant are amazing aren't they I just hope I can get them through another winter!