The tenant, whose name was not disclosed, has agreed to remove two break clauses at year 15 and 20 in its lease, which has 23 years remaining before expiry.
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"By successfully renegotiating this lease we have significantly enhanced the certainty of long-term income, which is now RPI (retail price index) linked and so creates an institutional quality asset,” said chief executive John Arnold.
"This is a major endorsement for the asset and further validates our active asset management approach. We anticipate this will be positive to NAV (net asset value)."