New ISP: getting 500kbs now, will I ever get more?

I've recently moved to another ISP. Now, from what I can understand, I'm supposed to see changes in the speed my line can sustain in the next 10 days as it settles down.

At the moment I'm only getting around 500kbs connection speeds.

With my former ISP, I got around 4-5mbs connection on an up to 8mbs package. This lasted for a good 6 months, then the ISP got taken over and my service was capped at around 2mb, for the same price.

With my new ISP I'm on an "up to 8mbs" package. Given that the speed I could get with my old ISP, could expect to get around the same 4-5mbs again with my new ISP?

Will getting some new filters help at all? I've one of those older wall socket with two ports things.

Many thanks.

Looks like your new ISP are rate limiting you [maybe?]. Who is the ISP and what are your line stats?

My ISP is Plusnet.

According to my modem it connects at 384 up / 3296 down.

Acording to http://speedtester.bt.com/

Test1 comprises of Best Effort Test: -provides background information.
IP profile for your line is - 2500 kbps
DSL connection rate: 384 kbps(UP-STREAM) 3296 kbps(DOWN-STREAM)
Actual IP throughput achieved during the test was - 494 kbps

However, I'm still, technically, within the 10 days since I was connected. Should I panic or not?