This is a stand alone Guacamole (https://guacamole.apache.org/) build with the config saved in a configuration xml file rather than a database and UK keymap included
Put your config XML in "config" directory and mount empty "data" directory for file transfers, in user-mapping.xml use the following
<param name="enable-drive">true</param>
<param name="drive-path">/file-transfer</param>
To use UK keyboard
<param name="server-layout">en-gb-qwerty</param>
Start with
docker run \
-it \
--name guac \
--rm \
-p 8080:8080 \
-v ${PWD}/config:/etc/guacamole \
-v ${PWD}/data:/file-transfer \
martinjohn/guacamole:latest
Then connect to docker server http://docker:8080/remote