There is nothing in principle wrong with using wagos to join earth wires.
However with a traditional UK pendant you would have neither the space nor the need to use a Wago for joining the earth wires, This makes me suspect you may be dealing with a fancy metal pendant. If so then that means one of two things.
1. If the fitting is "class 1" then you need to connect the earth wiring to the earth terminal.
2. If the fitting is "class 2" (aka "double insulated") then you need to use the provided terminal box and keep all connections and single insulated wires inside said terminal box. Given how stingy manufacturers often are with space in said terminal box that practically means having a single cable feeding the fitting.
Apologies to everyone I had a quick look before posting and the way I opened it the flex was covering the earth terminal. Thanks to you all for the replies
If you need to find a tradesperson to get your job done, please try our local search below,
or if you are doing it yourself you can find suppliers local to you.
Select the supplier or trade you require, enter your location to begin your search.
Please select a service and enter a location to continue...
Are you a trade or supplier? You can create your listing free at DIYnot Local