Downgrade from Infinity 2 to Infinity1

I have recently had a letter from BT listing the forthcoming price increases and offering me a small reduction to my Infinity 2 broadband if I sign up for 24 months.
It is still a lot more than Infinity 1 and I am wondering how much speed I will lose if I downgrade.
The BT checker this morning says that I am getting 57.9Mbps down and 15.31Mbps up with a latency of 33.13.
If I downgrade to "Up to 52" infinity1, will I get the full 52Mbps?
I am about 400 meres from a cabinet.

Yes you should (it's actually 55 meg sync) and you get above that already. So you'll lose about 5 meg downstream and the upload will decrease, but if it saves money .......

Thanks for that. Upload speed isn't that important to me.
Cheers

You will see no difference in general usage.

or do as I have and jump ship to PN, £10 a month cheaper and a 6mbs drop in speed comes as standard (Sam Knows figures, but no difference on TBB)