I'm still struggling to understand how you think this in any way invalidates the point I was making.
The original claim, entirely false, was that the UK Muslim Population would be greater than 50% of the total in 30 years. I promptly refuted this, by pointing out just how far it has to go in such a short time, and made an estimate (essentially back-of-the-envelope, but I don't need to do much more) that it would be, even at current rates, beyond my lifetime before this could happen.
This position is entirely supported by the link you have provided, as well as SP's, both of with estimate that somewhere around the middle of the century the Muslim population will have essentially doubled (at least as a proportion of the whole) from 2011 levels by 2050. This means that the total is somewhere near 10% in 35 years. That still leaves a further 40 percentage points to go to reach over half the UK population; it is not difficult to check that, continuing at the same rate, this would take a further 70-80 years after 2050 -- ie, current rates would have to be maintained for over a century. This is well beyond my expected lifespan, as I said.
This model is still too fast, though -- at some point, the same growth rate would predict that the total Muslim population within the UK will exceed that of the current population of the entire world (I reckon this will happen in about 2410). Hence the very idea of a sustain rate of growth at current levels falls down at some point, and rather quicker than 300 years too.
The present growth rate will not be sustained anyway (common sense is enough to confirm this); if it does, it will be beyond my lifetime before the population doubles (mathematics is enough to check that). This is based on the figures you have provided, and you are welcome to try the calculation for yourself if you still disagree. But ultimately the point is that a "30 years before we are overrun" prediction is utter rubbish and deserves to be condemned as such from all quarters.