Similar issue here, full fibre roll out is estimated to be complete in 2025.
I’m just outside Newcastle on the coast and could get Virgin but my neighbours have had a nightmare with it.
They only rolled out their fibre about three months ago so there might be issues with that
250GB - cache
1TB - Pool
2TB - Pool
10TB - Parity
With only 3TB in the pool you’re going to be increasing the size of the pool potentially quite quickly depending on if you’re ripping DVDs or Blu-Rays to it.
You’ll soon need another drive to boost that pool size and I promise, that parity will keep those tears at bay if something happens.