I have a '55 XK140 DHC that a previous owner upgraded the front brakes to calipers. The calipers are 3 piston with the marking DA 21589. They appear to be E-Type Series 3 calipers. I can source a seal kit for this easily. The big question is what is the flex hose part? I've included pictures of the hose and ends. The hose is 19 1/2" long tip to tip. One end is the traditional bolts to bracket and insert flare pipe...the other looks like an end for a drum cylinder and not one for a caliper. Any suggestions? They need to be replaced.

 

Not sure about your regulations.
In Australia there are numerous "hose doctors" or similar who can make you a brand-new brake hose with new fittings typically cheaper than retail outlets.
I have used them a number of times when restoring pre 1960 cars like Jag MK1, MK5 and MK7 when retailers can't even identify part numbers.
I simply take the old hose in to be used as a pattern.