Dispute with conservation area planning officer

[Tatlerer]

Hello
I've also posted in chat- apologies if you are forced to read my rant twice- but thought you ladies/ gents might have an additional opinion!

We are renovating a period (1920s) house that sits in a conservation area. The house needs new windows front and back. This was part of a wider planning application that was approved late last year (involving new extensions etc.).
We put a proposal in to replace the timber windows with UPVC. I know ppl have different thoughts on this but it's a massive project, we have an eye on the budget and timber is a ballache to maintain. The planning application was granted with the insistence the timber frames were replaced with timber (at the front of the property- they don't care about the back!).
Anyway, I'd spotted houses in the area with woodgrain UPVC windows and challenged this with our planning officer. He came back on email to say that yes, some applications had been passed for woodgrain UPVC, reiterated they must be 'high quality' and designed to look as close to the originals as possible, sent me a link to a supplier. All good.
Part of the planning process is that we must share a sample/brochure of the windows we're intending to use, before ordering. Again, fine. Two days ago I sent the very same.
I've now had an email back from the planning officer and he's 'spoken at length' with the conservation team and they're insisting on timber again! They say that the examples of passed UPVC applications are ones where the inhabitants were replacing UPVC (installed before the conservation order came into force) with more UPVC.
My questions are:

1. putting your personal feelings about UPVC vs wood aside (FYI we're never selling this house when it's done!)- am I right to feel seriously misled by this?? I've emailed the planning officer to request a discussion but can I challenge this in any way do you know? The cost differential will be significant and on the basis of his first set of advice we built the budget for the whole works around UPVC... and
2. if the above is fruitless, would it be really odd to have UPVC at the back and timber at the front??? Thanks in advance

I don't think you were misled and it is very unusual to be able to use uPVC in a conservation area. I think the planning officer sounds as if he was trying to be helpful but was overruled.

No, I don't think it matters if the house has different windows at the back as long as all the windows on that elevation are consistent.

100% doesn't matter if the front and back are different.

Slightly annoying you were told one thing and now you can't have the wood grain UPVC but houses in conservation areas come with niggles like this.

Thanks for your reply lala. I guess I feel misled as he knew the exact details of my house (that we were intending to replace timber with woodgrain) and said that it should be fine. Equally when I spoke to him yesterday to check he'd received my latest email with the specs on he said 'should be ok, we're just looking for you to replicate the details' and I reiterated that the leading, design, everything would be copied.

Thanks hipster. that's one way we can save on upfront cost and ongoing maintenance at least, so it's what we're leaning towards at present.

Timber windows really shouldn't take too much maintenance and you can get creative with colour unlike uPVC! Also it's more environmentally friendly! (Just trying to give you a positive slant here!)

Thanks olivia and I appreciate it! No creativity with colour allowed however- another stipulation of the conservation order is that they must be painted the colour they are now (white!).