Non-perturbative determination of improvement coefficients $$b_\mathrm{m}$$ b m and $$b_\mathrm{A}-b_\mathrm{P}$$ b A - b P and normalisation factor $$Z_\mathrm{m}Z_\mathrm{P}/Z_\mathrm{A}$$ Z m Z P / Z A with $$N_\mathrm{f}= 3$$ N f = 3 Wilson fermions: ALPHA Collaboration