The garage at our house is located at the end of the garden about about 15 metres away from the house and the power is supplied to it by a single heavy duty cable from the consumer unit with a 30 Amp feed. I am in the process for building a music studio in the garage and would like to add further sockets for amps, lights, mixing desk etc. Should I plan on having a roing main that loop's back to the single heavy duty cable to help the distribution??
Sorry but not really enough information. But 30 amp is a far bit of power and if all was done correctly in first place then it should be OK, but to work this out you need meters that cost about Â£700 so cheapest was is to call in an electrician and get his advice. Bad installations do have a fire risk and even if the Law did not require an electrician who is qualified to do the work it is far better to get someone in to do the job. In other words if you need to ask the question you should not be doing the work.
As to if ring main or spurs ring main easy way out. There are so many considerations with spurs, fuse sizes, Where fuses are fitted etc.
Remember even if you use four way splitters that plug in if you tidy up cables by putting a few clips on them if comes under Part P which not complying with will invalid insurance.
Sorry to be Negative but I think your safety from fire is more important than saving a few pounds.