Is hashimotos goitre always going to be there, or is this condition reversible ?

Often to a degree: Hi. Hashimoto's goiters often regress over long periods of time and may regress completely, but often a goiter remains. I know that's not very exact or helpful, but at least you know it's fair to expect some degree of longterm goiter. If it grows rapidly or significantly or develops a nodule, it should be evaluated. Good luck!