Brown bin food recyling - what can you put in?

[Mrs TP]

A relative who lives outside of London told me they are not allowed to put kitchen oils / fats or pet food in their food recycling bags. They still get free bags from their local authority and excluded kitchen items are specifically listed on the bags.

I checked out the Southwark website guidelines and it does not show fats and pet food in it's list of accepted items.

Have I been doing it wrong all these years? Anyone else? A revelation to me.