For "Pre-meditated wounding or GBH involving the use of a weapon acquired prior to the offence and carried to the scene with specific intent to injure the victim (but not resulting in a life threatening injury or particularly grave injury)" judges are required to work from a 'starting point' sentence of 8 years imprisonment and, after considering all of the relevant circumstances, actually pass a sentence of between 7 and 10 years. (A judge can only pass a sentence outside of those guidelines if there are genuinely exceptional circumstances, which he/she must explain in open court).
However those sentences refer to a first time offender convicted after a trial. An early guilty plea can see the sentence cut by one third. Further, the actual time spent in prison is usually only half of the nominal sentence.
So, based upon your description of the offence, I'd guess at a sentence of around 7½ years, reduced by one third to 5 years, with 2½ years actually being spent 'inside'.
It's likely that sentencing for the other offences would be concurrent, and so can effectively be ignored.
However I note that you state that "The victim required minor treatment at hospital". If that's the case, the offender should seek legal advice as to whether it might be possible to get the charge reduced to ABH. Read through paragraphs 45 to 58 here, to see the difference between ABH and GBH. (If GBH is appropriate the premeditation involved will almost automatically add 'with intent' to the charge but there's no such charge as 'ABH with intent'):
http://www.cps.gov.uk...he_person/#P189_14382
For confirmation of the sentencing guidelines I've cited, see page 13 here. (See page 17 for ABH sentencing):
18:32 Mon 08th Nov 2010