Breast cancer-related upper limb lymphoedema (BCRL) affects approximately 20 % of women undergoing axillary intervention. Women who attended a "reducing your risk of lymphoedema" class, including exercise instruction, anecdotally reported positive BCRL outcomes. The aim of this study was to examine BCRL outcomes and perceived benefit for attendees at a "reducing your risk of lymphoedema" class between 2000 and 2005. A cross-sectional study was conducted in two parts: (1) self-report questionnaire regarding lymphoedema status and benefit received from class and exercise programme; (2) clinical evaluation and objective measurement to confirm BCRL. 46 women completed questionnaires; 40 continued to clinical evaluation and objective measurement. BCRL prevalence defined as ≥10 % excess limb volume was only 5 %, although clinician judgement identified 23 % with arm lymphoedema and 8 % with lymphoedema limited to the hand. Clinician judgement correlated highly with patient self-report (Kappa = 0.833, p = 0.000). All women found the class beneficial, reporting increased confidence to return to normal life and a wide range of activities/exercise. We conclude that prevalence of BCRL should be determined by both clinical judgement and objective measurement to avoid underestimation. The benefit of group education with a lymphoedema expert and of exercise instruction should be further explored, and the potential for exercise to reduce BCRL prevalence should be examined.