Stuck fermentation

[yog]

Help needed please. Brewed 5bbl of pale ale og 1.050. pitched 5lbs house yeast at 21C and went away. Have brewed this beer many times. Over weekend, temp in brewery dropped below 0C for first time this year (-6C according to thermometer) Normally would be down at 1.011 by now and would be cropping yeast and starting chill routine. however cold temps for two days over weekend have dropped temp in FV to 4C and ferm has stalled at 1.025.
Question is, is it better to warm the fv and rouse and re-pitch, or can i brew second batch of this beer and dump it on top, effectively blending the two? The new wort would be mixed in at 35C in order to bring overall temp up

[froptus]

Either method should work fine. Do which ever one is easier. I'm currently working in a 7 bbl brewhouse and sometimes my co worker forgets to reset the temp controller to 68 and leaves it at 33 and turns the jacket on at the beginning of a fermentation. An easy technique I use is to shove a space heater under the fermenter (a dish bottom fermenter). It has worked quite well.