Storage is an allowable expense, so self storage units are fully tax deductible. If you are VAT registered, you can claim back the VAT you are charged.
This does mean that you need to be using the storage for business purposes, rather than just personal storage.
If VAT isn’t being charged, you cannot claim it back and you will have to pay full price. However, VAT is legally chargeable on self storage so if that isn’t happening, you should ask why that is.
You can find more details about tax deductible expenses on the government website here.
We have put together a handy guide to answering more questions about self storage which you can find here; 7.5 Questions you must ask before choosing a self storage facility