BNI ,you can pay £10 for a visitors fee (as long as no other window cleaning company is in the group) thats what I did,for residential work I think its a no go,commercial maybe yes,being a visitor you still get the chance to get up and do a breif presentation of the nature of your biz and exchange promotional leaflets biz cards with the members,I had good feedback from this meeting and now do 2 £20 houses 1 £25 house (next 2 each other monthly) and have a good commercial contract from this,will be visiting a local BOB meeting in the new year.Membership to expensive for WC sole traders IMO just be a visitor
Heath