I did tesco avonmouth for years its a ■■■■ easy job once you relax. Some stores have tight and difficult reverses, just do it slow an the staff will help if you ask.
As for heavy cages you only have to get them to the end of the trailer an the staff do the rest. You have to chat to them and they will be more than helpfull, have an attitude an they will watch you struggle.
Adjust the air suspension so front is slightly higher then gravity moves the cages for you…