Brakes a bleeding nightmare

Help, I am having an absolute nightmare with the drum brakes on my series 3. I noticed the front left hand wheel cylinder was leaking badly so decided to replace both fronts and the flexis while I was at it. All done and then I couldn't get it to bleed. Got a reasonable firm pedal but the minute I got it off the axle stands and drove it straight to the floor. So I then replaced the master cylinder and the down pipe to the splitter. Have bled and bled it using a vacuum bleeder and an assistant and pedal still travels all the way to the floor. Have tried clamping the cylinders in with a ratchet strap and still no luck. At my wits end with the bloody thing

The manual is here and tells you how to bleed properly, what set up do you have , have you. Got the twin leading 11” drums on front

Clamping all three flexis is the place to start to find where the problem is , and go from there as in the manual
Did the shoes get brake fluid in them, have you got the springs on properly

I didn't have the springs on properly but do now. Will try clamping the hoses as you suggest thanks

So clamped front hoses and got a solid pedal, so must be an issue with the front brakes. Clamped each side in turn and it appears to be front left. Tightened up connections and pedal now seems better??? Haven't tried driving yet though.

That’s good progress did you get some air out, have you got 2 wheel cylinders at each front wheel , there is a few other things to try if brakes still not adequate

I didn't try bleeding it yet, too hot today! I only have one wheel cylinder on the fronts