I don't usually post details of children not otherwise publicised in family notices placed in the newspapers, etc., however, this is an heir in direct line, so will make a bit of an exception.
According to the GRO indices Arthur I G HAZLERIGG was born to Hon Arthur William Grey HAZLERIGG (born 1987), son of the 3rd Baron HAZLERIGG (born 1951) and Laura DUGDALE (born 1953), dau of Sir William DUGDALE, 2nd Baronet (1922 - 2014) and Lady Belinda PLEYDELL-BOUVERIE (1925 - 1961) of the RADNOR earls, by his 2017 m to Kate Sarah BRAITHWAITE.
The birth was registered in Q1 2020 Westminster. I have suppressed his first middle name which can be seen on the indices. His second middle name can only be seen as an initial, but if you look at the names commonly used amongst Hazlerigg males, you can probably make a good guess!
The infant is his now second in direct line to his grandfather's barony.