Thanks for your enquiry.
I am slightly confused as to who owns what. So, a third party owns the house? Does some other third party own the garden and you own some land adjoining the garden?
I look forward to hearing from you.
Thanks for clarifying matters.
Well, as the land and the house are in separate ownership, any rights which the house owner has do not transfer/apply to the land.
Hence, if no specific right of way has been granted in favour of the land, then any owner of the land does NOT have any legal right of way over your land. Your land therefore becomes "a ransom strip".
I hope this confirms the legal position, but please let me know if you require any further assistance.
If not, please don't forget to rate my answer.
It is just basic property law- there is no Statute applicable to this issue.