new build work utr number

[cme electrics]

hi all,ive been working for many years as employee (electrician/tester) and recently a friend of mine asked me to help him doing some second fix on a new build flats. ive still got my utr number,my question is do i need to do anything else such as register as solo trader or limited company?the agreement with him is to provide him invoice every week..do i need something more than utr num?
thank you all

 

[westward10]

If you have a UTR then you must have applied for it so it should be fine unless anyone knows different. Did you register through the CIS scheme and do they pay through the CIS ?