Now that you mention it, we're feeding her more wet food as I've had to move temporarily whilst waiting for my flat to be ready and she was hardly eating her usual dry stuff.
Wet food often causes smellier stools, and a change of diet can disrupt your cat's digestion. A temporary move will also cause a bit of stress. If she was eating dry food before, I would return to that unless she is refusing it entirely. Cats don't like change, and if she has a new home and different food, this will be likely to upset her.
Nonetheless, both long and short haired cats sometimes suffer from smelly hindquarters, but only if they are not grooming properly. Disrupted or incomplete grooming will be due to stress as above - she doesn't feel comfortable in a new space (constantly anticipating surprises in the unfamiliar territory, for example, meaning she's not taking a long time to clean. Any student of cat behaviour will know a relaxed cat grooming thoroughly, for what can seem like hours. Cats hate uncleanliness with a passion.
Before changing anything about her litter tray, observe her behaviour when at toilet and grooming afterwards. Does she seem nervous - does she clean straight afterwards, and in the open or seeking a hidden space first? I note this because cats used to a covered tray often get really panicked by an open tray - removing the cover will make her feel even more exposed, and perhaps even more likely to rush her toilet.
Finally, it may be the case that her hair is simply too long and fine to groom properly. If it seems this is the case, it should be easy to trim a bit. Far easier than
surviving scheduling a regular bath, anyway!
In short, I'd go back to feeding her previous dry food and provide a nice big cardboard box for her to hide in not too far from the litter tray. Watch her behaviour for a week or so, look for any signs she's nervous.
PS Just a thought: I assume she's regularly wormed, but if not, ensure this is the case. Wet food especially can introduce parasite eggs and a worm infection can contribute to poor hygiene.