Man walks after assault on racer's son

A man has been granted immediate parole after pleading guilty to assaulting motor racing champion Gregg Hansford's son.

Christiaan Michael Brockhurst-Challoner, 22, repeatedly punched Harrison Donovan-Hansford in the head and face during a prolonged attack at a Kangaroo Point unit in November 2015.

The Brisbane District Court heard on Thursday that Brockhurst went to the unit to "sort out" the 21-year-old, who he believed had been treating women badly and spreading rumours.

Brockhurst ordered Mr Donovan-Hansford into the bedroom where he punched him 10 times, causing him to fall onto the bed.

Camryn Ruadhri Lloyd and another man also kicked and punched the victim while he was down.

Mr Donovan-Hansford was then told to wait in the lounge room, where he was assaulted again by Lloyd and a fourth man, Mariner Thorpe Rood.

As a result of the blows, Mr Donovan-Hansford suffered fractures to his eye socket, nose and ribs.

The court heard Brockhurst was the "instigator" of the assault and went to the unit with a plan to attack while the other men just happened to be there.

Brockhurst was due to stand trial on Wednesday for torture and kidnapping but instead pleaded guilty to less serious charges of assault occasioning bodily harm and deprivation of liberty.

He was sentenced to 18 months in prison but granted immediate parole having already spent about two months in remand.

Lloyd and Rood will be sentenced for their roles in the attack on March 24.

An arrest warrant has been issued for the remaining alleged attacker after he failed to appear in court this week.