M Wright

Hello, I am hoping to undertake some short-term self-employed work in Europe this summer and am needing to apply for an A1 certificate (using the CA3837 form). I understand that if you have been registered as a sole trader for less than 2 months prior to applying that additional evidence of self-employment is required to support the A1 application. Would anyone know or have experience with what specific evidence is needed for this? I am still full-time employed but have been doing a small amount of self-employed work on the side. Would generating a few small invoices from self-employed work over a couple of months be sufficient, or would I be expected to have self-employment as my only source of income for this 2 month period? Any help would be much appreciated.