All bowlers who wish to take part in competitive bowling under the rules of the BCGBA (league bowling, competitive bowling, etc.) must have a BCGBA number. These can be acquired for £10 from a county registrar and is a one-off life time fee to become a member of the BCGBA.
Clothing Bowls wear for the novice is very straightforward. Flat-soled shoes/trainers and clothes that you feel comfortable in to "bend and send". Generally league matches simply require you to be dressed to a socially decent standard - a shirt must be worn - but some leagues are more stringent than others.