DTGK

[SirJ]

24d Garden structure for growing sweet peas clematis runner beans or other climbing plants. Letters appear to be -B-L-S- if 28 ac is "Britten". The only words I can come up with with these letters are Obelisk and Tbilisi!

[mazie]

it's Obelisk

[SirJ]

Thanks Mazie, that surprises me because when I searched for a definition of obelisk I just came up with the Cleopatra's Needle variety i.e. an upright 4-sided usually monolithic pillar that gradually tapers as it rises and terminates in a pyramid. But you live and learn....