You shouldn't get much smell while it's fermenting - if you do it means your hop aromas are escaping rather then going into your beer!
Regarding temperature, there's a lot of thermal inertia in 5 or 10 or 20L of fermenting beer and it takes a lot of heat added or removed to change its temperature significantly. But I do recommend those cheap stick on thermometers for the outside of your FV so you can keep an eye.
Nevertheless, one thing you can do is sit your fermenter in a bucket or crate of water (see below), this will create even more thermal inertia and help maintain stable temperatures. You can add ice blocks to the water bath to lower temperatures - in this case it was for a lager fermentation, but you can do the same with ale yeast, just keep the temperature a little higher:
https://www.thehomebrewforum.co.uk/threads/matt76s-brewdays.81971/page-2#post-830155
I've got a nasty feeling my brew may have stalled, possibly due to having it in the porch which was too hot during the day.
I brought it into the hallway which is much cooler but, it hasn't been giving off any beer smells for a few days now and the krausen production seems to have stopped too. However, the temperature on the sticky thermometer is at 23c which may suggest some activity still going on.
Do I need to open the lid and check the gravity over 24hrs to see if anything is happening?
Many thanks