might be a bit hard now hes settled into it though at 1 year it not impossible to retrain id say. if you do it everyday for 15-30mins he should get the idea within a couple of weeks - he should really get it within a day or two really then just be testing you. having him sit a kerb sides for periods of time helps them listen and settle, i find if i say good boy when my lads heeling it sets him off so i usually dont say anything apart from 'heel' - if he gets infront i might give him a short 'hey' and he comes back. if hes good let him have some off lead play, if hes bad - enjoy the training untill you get home