There is only the observable Universe.

The Universe is expanding at exactly the velocity of light.

This explains cosmic isotropic as 'c' has always been the same.

The Universe is closed, positively curved and asymptotically flat.

Note that HD 140283 is estimated to be 14.46±0.8 billion years old.

Recent CMB by the Planck satellite give a value of 66.8713 km/s per Mpc.

Derivation of the Hubble-Slipher Constant for a Universe age
of 14.62231 billion years given a velocity-of-light expansion rate.
Kilometers in a megaparsec: 3.08567758 × 1019
One year = 31,556,926 seconds
Universe at age UAge is t = 14.62231 billion years. Assumed.
Universe UAge is t = 31,556,926 × 14.62231 × 109 = 4.6143515 × 1017 seconds
Diameter ct = 299,792.458 km/sec × 4.6143515 × 1017 sec = 1.38334779 x 1023 km
Diameter is ct = 1.38334779 × 1023 / 3.08567758 × 1019 mega parsecs
Universe Diameter is ct = 4483.1249 mega parsecs
Hubble-Slipher Constant is H = c per UD = velocity of light per Universe Diameter
H0 = 299,792.458 km/sec per 4483.1249 mega parsec
H0 = 66.8713 km/s per Mega Parsec

       For different assumed Universe Ages here are corresponding Hubble values.

Universe Age Hubble Constant
13.50 72.300
13.60 71.815
13.70 71.330
13.80 70.845
13.90 70.347
14.00 69.875
14.10 69.390
14.20 68.905
14.30 68.420
14.40 67.935
14.50 67.450
14.62 66.869
14.70 66.481
14.80 65.966
14.90 65.511
15.00 65.026