That is complete cr*p, frankly. It looks a long way on the maps but the Canary Wharf estate is fundamentally very small. The walk from the hotel to the shopping centre would be 90 seconds, probably, followed by probably 60-90 seconds walking through the shopping centre and then 20-30 seconds outside (assuming you leave at street level) to the top of the tube escalators. Even with a modest stroll it is probably 6 minutes max.

DLR is even closer, within 3-4 minutes of leaving the hotel I would guess.

Now, if you've got 3 suitcases then it will be a stretch but with a rollaway you'll be more than fine. You could even hail a cab outside the tube to run you round the corner (but don't take one off a rank or the driver will want to kill you.)

Put it this way. It is as close to the tube as FS Park Lane is to the tube, once you've negotiated the Hyde Park subway.

There were also no major tube closures last weekend. A lot on the DLR but the tube was fairly clear apart from some platform switching at Paddington. You would usually expect to see about 10% of the tube closed at weekends.