This is the bonus cache for the Adventure Lab Cache Roath Park Lake and Botanic Garden. On completing each stage of the Lab cache you will be given a number to to be substituted within the following formula to obtain the final co-ordinates:
N51 30.ABC W3 10.BDE
You are looking for a small sized geocache container.
Please note that the terrain rating of this cache incereases significantly after heavy rain and may be unsuitable for those with children.
If you are having trouble finding the Adventure Lab cache then here is a link:
Roath Park Lake and Botanic Garden Adventure Lab Cache