LCWRA and permitted income

Hi I have a joint UC claim with my partner as I had to stop work 3 years ago to be his carer. He was awarded LCWRA 3 months after the initial UC claim date. I'm sure that I've read somewhere recently that if you get LCWRA you can have some income and it doesn't affect your UC......does anyone know where I can find this info. The reason for my question is that both my tiny private pension and the puny carers allowance are classed as income and deducted from our joint UC claim. Surely as a joint claim, if there's any substance to what I've read somewhere then I should be able to 'earn' without it affecting our UC .........my partner has a very rare disease with no cure and has just had an SR1 form raised to DWP, resulting in enhanced PIP for both elements and no health assessments for PIP or UC and continued LCWRA.