Two huge Buxus spirals in planters, need help please!

Hello all.
I purchased (last month) two 6 ft huge Buxus spirals. They came from a Dutch nursey as I was unable to find any local to me (I'm in Scotland).
They arrived in smallish pots about 50cm across and 40cm deep. They looked healthy and green, but with quite a bit of dry dead looking bare twigs in the middle which I pruned out to allow more air and light inside the trees.
I planted them into much larger planters measuring 55cm across and 55 cm high, made of fibre clay with a large drainage hole in the bottom.
I used John Innes 3, a handful of garden lime (as I read that Buxus like this), dug in some grit, added a handful of Buxus feed, and a handful of Mycorrizial fungi to help establish the roots. I have mulched around the plants with chipped bark.
I did loosen the rootballs before planting as they were very tight and looked a little root bound.
I planted them at the same depth as the original pots.
Since planting, the trees have begun to take on a sickish yellowish/bronze cast, I've found some extremely tan coloured and almost white leaves, and a lot of the leaf tips have almost a chewed/brownish look to them.
Now, I don't know if this is scorching (thinking that maybe the nursery trimmed it before sending it to me and the edges of the leaves have subsequently scorched) or if something is actually chewing the leaves. I can see no sign of caterpillars or webbing but I did see one moth hanging around the Buxus which flew away before I had a chance to identify it as a Box moth. I used the XenTari Box moth treatment last week and have sprayed them both just to be sure.
I have also sprayed them with the TopBuxus Health Mix to prevent blight incase it's the start of blight.
I have been watering twice a week but don't want to over water as I'm concerned about root rot in the planters.
No new growth has appeared on them since I received them.
I just want them to green up a bit but I don't want to OVER fertilize them (I dug in fertilizer at planting).
What else can I do? These were hugely expensive specimens and I really want to give them every chance. I was advised on another site to put them in bigger planters but these planters are absolutely humungous already and come up to my waist almost, I really can't get bigger ones!
I've attached some pictures and close up pics of the leaves.
I would appreciate any help or advice.
Thanks all.

 

To be honest I cant see anything drastically wrong.

Looks like they might have had a slight attack from the moths but really I would expect them to look like they do at this time of the year.

I wouldn't expect much new growth at this time of the year.

May well have had a last minute trim before sending them out.

 

Look like they have been recently " shaped " by the nursery.

Its been a lot warmer in Holland than its been in Scotland this year so plants will just be settling into its new enviroment.