Late to this, but we had the same thing on ours. Starting price was £40k, but we incurred hidden extras, like needing a chimney stack removed (for the rear bedroom), dropping the ceilings in the existing bedrooms to gain enough head-height for building regs. Also, we retrospectively factored-in a skylight over the new stairs, which in hindsight is a must-have.
Late to this, but we had the same thing on ours. Starting price was £40k, but we incurred hidden extras, like needing a chimney stack removed (for the rear bedroom), dropping the ceilings in the existing bedrooms to gain enough head-height for building regs. Also, we retrospectively factored-in a skylight over the new stairs, which in hindsight is a must-have.