An update, although not a good one

Draytek support provided a new firmware file, upon checking its exactly the same as one already provided and tested on the 28th March, same name, date, size and checksum, looks like they are just trying to fob me off while they are unable to resolve the issue.

I have requested the process to return the unit as its not fit for purpose, I opened the ticket with Draytek on the 6th March and the issue is still not resolved, even though its proven that mine is not an isolated case, I am willing to bet all 2750s are the same if users actually performed before / after comparisons.

Did you double check if they have make mistake and send same file by accident? However if you still can return the unit is not bad idea either...i have ordered an 2760n (but i only have adsl)
http://www.forum.draytek.co.uk/viewtopic.php?f=15&t=18350&p=76344#p76242
... so are you going to give a swap with it? ... or not sure at this point? If your original BT modem is ECI should not have problem ... if is the huawei then not sure

I did email Draytek support and are awaiting their response.

This router was purchased on 13th Feb but ive yet to use it in production apart from completing tests for Draytek support, all of which produced the same result

The latest response was to point me to the latest stable release 1.5.3 which we all know doesn't fix the issue.

Draytek supplied a new BETA firmware which we tried yesterday, the results are the same, the upload speed is still approx 50% that of the BT equipment.

This firmware also introduced instability, menu errors as things like the VDSL menu just disappeared, the connection took ages to establish and in some cases required a reboot to connect.

Switching back to the BT equipment everything connected and upload speed returned to normal.

Only posting to be patient ... i know how you feel
If they done it with one model should fix and with this one ... keep faith