I have 4 David Austin, Heritage--lovely, lots of blooms all season, very super disease resistant, tons of petals, beautiful light to pale pink, beautiful dark green foliage, gets huge though.
Also have a Fair Bianca. Same type of petals (lots of petals) white, again very disease resistant, healthy
Pat Austin--Very pretty orange yellow blooms. Healthy--disease resistant. Would probably never plant this one again because blooms droop (stems don't seem to hold up the bloom longer than a day after it opens)
Then there is the Othello. Very vibrant fuschia color. Would never plant this one ever again. The thorns are awful--would just about take a finger off if not careful. Plus they seem to bloom a couple times & then nothing for the rest of the season. Don't know if this was just a problem with my Othello or if all Othellos are like this.

I checked out the ones you listed. I think the Mary Rose one is the prettiest. A friend of mine planted a bush at her old home & dug it out to take it to her new home she loved it so much. Looks like you want to stay in the pink family?

I had Harlow Carr in the past but it did not at all like my hot and dry climate. I have read comments that it's very thorny when it gets older and the bush doesn't look all that great but have no personal knowledge. I also had Mary Rose and it is pretty, but the blooms shatter very quickly and it was rather thorny and obnoxious when deadheading. I don't know that I'd consider those major faults, however.

Ingrid

Among the roses you listed, I have Abe Darby (4 years) and Harlow Carr (2 years). I am in Northern Jersey so our climates should be similar enough. Both get some blackspot, but nothing terrible. I don't spray. However, Harlow Carr is a compact rose (in Austin lingo, "mannerly" grower). Abe is far bigger, sprawling shrub. You should be aware of the differences in size/growth. I am not familiar with the two other roses you mentioned.

Local nurseries don't stock many Austins here either. A few of them here do offer potted Austins at $50 or so a pop. You might want to order potted roses directly from DA in Texas or get bands.

Harlow Carr and The Mayflower have wonderful, strong fragrance. Mary Rose is not as fragrant.

The Mayflower has an upright growth habit. Mine is about 4 1/2 feet tall, I'm in zone 5.

Harlow Carr is fairly new to my garden, but I think it won't grow as tall as The Mayflower.