Hello. I found that Kroger's "Simple Truth Organic" English Breakfast Tea is a decent stand in. Not as great as St.Dalfour mind you, but it comes pretty close imo.

kroger.com/p/simple-truth-organic-english-breakfast-black-tea-bags/0001111005414?fulfillment=SHIP&searchType=default_search

I like to mix it with this brand I found on Amazon. It really hits those notes from Delfour when steeped together.

amazon.com/gp/product/B0007R72HK/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1