I’m no expert but this website states
”In Brief
GBH (grievous bodily harm) with intent is a Section 18 offence rather than a lesser Section 20 offence. Assault can be committed recklessly or intentionally, so to prove intent it must be demonstrated that the offender both caused severe injuries and intended to cause them. Factors indicating intent include evidence of planning and prior threats, repeated or sustained assault, the choice of offensive weapon and excessive force such as kicking the head with a shod foot. The maximum punishment for GBH with intent is a life sentence.”
”The injury – although it may affect the severity of the sentence – is not a determining factor in distinguishing whether GBH was committed recklessly or intentionally. Often however, it may provide some evidence of intent i.e. if the defendant left home in possession of a sharp knife, then located and stabbed the victim.
The prosecution and the police will sometimes assert that if the injuries are very serious or life threatening that it must have been the case that the offender had intended to cause them.
In law, this is what is known as a rebuttable presumption, whereby it is possible to refute this assertion by calling defence evidence to show that as much as the injuries may have been caused by the offender, it was not their intention to have done so.
In these types of scenarios, it may be the case that the offence is more akin to an offence contrary to Section 20 OAPA on the basis that the injuries had been caused recklessly rather than intentionally.”
”For a Section 18 GBH charge to be proven, it must be shown that the offender physically caused the serious injuries and, at the same time as the assault took place, that this is what they intended to cause. It is the intention or knowledge of wrongdoing that constitutes part of a crime.
For a case to be considered under Section 18, identifying reckless behaviour in the actions of the offender will not be sufficient enough to find an accused individual guilty. The act must be malicious in nature and deliberate, indicating malice aforethought often with a degree of premeditation.
Factors which may indicate higher levels of culpability for GBH with intent include:
A repeated or sustained attack
Evidence of planning of the attack
The deliberate choice of an offensive weapon or an equivalent such as a razor blade
Unlawful force such as kicking the victim’s head with a shod foot”
www.lawtonslaw.co.uk/resources/what-constitutes-gbh-with-intent/