I am not familiar with either of them. There is a detailed description of Crataegus x sinaica in Vicflora https://vicflora.rbg.vic.gov.au/flora/taxon/83c93f37-5402-4e8d-8942-5f0dd1647159 If that helps.
Mike twelve species of Hawthorn were grown at Yarralumla Nursery between 1915 and 1980. Crataegus laevigata was the most popular planting followed by C. phaenopyrum, C. monogyna and C. crus-galli. I have cut out Crus-galli from Red Hill, while C. monogyna is a widespread weed. Of the twelve only C. monogyna and C. azarolus look like the plant in your photo, with C. azarolus being the most likely, though a form of C. monogyna can't be totally dismissed.