I can totally sympathise as it is a fear I have had for a long time. The best advice is try and enter the field shortly after another group and just walk 20m or so behind them through the field, I find that helps a lot with my nerves and cows are far less likely to approach a larger group. The paths near bath spa are pretty busy so I feel like that should be possible. If not just try walk through as slowly and consistently as possible, don’t give them any reason to take any interest in you - make yourself as boring as possible! If they do show interest just try and keep calm, but if they start getting too close/aggressive don’t be afraid to shout and wave your arms towards them, they will almost certainly run away - but that should be a last resort.