All my wholesalers stock them - I assumed it was nationwide.
They are typically 60 or 80 amp.
Most domestic properties are not going to ever exceed this, and indeed the majority of service heads have an 80 amp or lower fuse. Rare to see a 100amp even though the service head is usually marked as such.
What is the loading of your "100amp consumer unit"? What is supplied? Immersions? Showers? Elec heating?
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