Variegated Holly Ilex Golden King

Hello,
I recently transfered the above holly from my fathers garden,as he passed away.It was well estabilished in a large barrel with bottom cut out.We had a terrible time being careful with roots,as we thought it was just in barrel,not buried into ground.However I dug a deep hole ,mixed bonemeal with some compost and planted.It seems to be none the worse of the flitting,but it is rather large and could do with a trim.Can you nice experts advise when would it be best to give a haircut to this holly.I really want to protect this shrub and don,t want to take any risks.The shrub/plant is 34'' tall and is almost same in diameter.I dug a 24'' diameter base and have recently put bark chips around this base,is this also sufficient.I have been regularly watering and the occassional drink of miracle grow,once a fortnight roughly.

 

If you think about holly its always on sale for Christmas,
if you have a sprig in your house over Christmas and New Year its supposed to be lucky for the following year,
So i would clip it about that time
I had 6 bog standard hollies given to me last autumn,as i was going away and didnt want it in my garden i left it up the corner ,in June i decided to plant them against the wall outside my property, so they would help the current hedge ,as a intruder deterent,
They have settled in and 1or2 have the signs of berries on them