The yeast with almost all Muntons made kits is the same. I am told that it is basically Nottingham yeast, which makes beer that is archetypically English.
I stopped trusting it a very long time ago, because I have no temperature contol over fermentation.
Centrally heated houses typically are just too warm for this yeast, which is fine at 18-20C absolute max. Unless you have a brewing fridge, the initial temp will send your Muntons yeast into a lazy, statis, sort of mode, rather than conversion.
The yeast that comes with Coopers kits is OK because it has been genetically modified by selection to brew good beer at these 20-22C temps, and still work at upwards of this.
I use US 05 by default now, for these reasons, although it does need 14 days in primary and a further 7 days in a secondary FV, in my slightly limited experience.