Now on FTTC but do I need to do anything else or not.

[#1]

BT Engineer came this morning and everything went very smoothly. My first speed tests were showing mid 20's Mbps but now after a few hours I'm down to 512K or less. I know that it takes a while until everything stabilses but are these vast differences normal? I've been getting very consistent ~950K speeds for a long time now so for the time being I'm down to half the speed I was getting before the upgrade. I'm not sure if I need to do anything or just sit back and wait - at least I've still got a connection.

[#2]

I've just updated your connection profile. See what the speeds are like now

[#3]

30359kbps down and 1698kbps up - Thank you Adam.
I was unsure after reading in the forum that this was now being done before the actual upgrade. I'm certainly happy with that. I think I still have some issues to sort out as response times (as opposed to speed) are really slow but that's probably a wireless issue and I'll do more testing when I've got my office straight again and the desktop re-connected. I'm wireless at the moment two floors below the router.
p.s. - by the way, it's the personal rapid service that we get from Plus Net that makes all the difference - it is appreciated!