I was paying for an "up to 76Mb" package but only ever received about 32Mb maximum (but more usually 26Mb or so) so I "downgraded" to an "up to 36Mb" package to save a bit of cash (same ISP). Interestingly when the package changed my speeds actually went up, I now get a consistent 35Mb download.

Oh, I see what you mean.

I appreciate I am about to mention a different model, but...

I have a 2860 connected to the faster of BT's 2 Infinity services. For a long time that connection ran flawlessly at 80000kpbs down and 20000kbps up... Then, about a year ago, I started to notice a degradation in performance, with the line at first slowly fading and then dropping alarmingly down to under 20000kbps for downloads... In the process of getting this fixed I learned that:-

1. In your router's "Online Status -> Physical Connection" display, you can see the actual rate-negotiated line speed. Sometimes a power recycle can "clear" issues as it forces the two ends of the link between you and the cabinet outside to re-negotiate the best performance link...

2. The quoted value of SNR seems to be a good indicator of link health. Counter-intuitively, [according to multiple BT engineers] the lower the SNR the better... because, they claim, this indicates that the link shows little noise on the line. I've just checked my 2860 and in the last 2-3 days my line speed for downstream has slowed from about 71000kbps to 68740kbps, but I notice that the SNR has gone up to 9db upstream and 6db downstream...

Having used Draytek kit since ADSL1 was introduced... in my experience to date, any performance that has been less than the theoretical maximum has always been down to BT...