Crystal white dress help please

Hello I'm wondering if anyone can help me please. Im getting married in August and have my heart set on a particular dress which is-
Pronovias- Alesandra.
I've been looking online for second-hand ones as it's just too expensive new but most that I find are Ivory or an off white and I'm looking for diamond white which I know they do.
If anyone knows of anywhere selling it or has it themselves they would sell or let me rent from them I'd be extremely grateful.
I know the ivory and off white is beautiful I just had my heart set on having pure white.
Most dresses I try are around a size 12 but any bigger I could have altered if I bought.

But if anyone does have a ballgown style wedding dress in white that isn't the make I mentioned I'd be interested in that too.

I was also wondering if anyone knows anywhere to hire pale grey tailcoat suits because any I find are a darker grey.

Thanks so much