There are several different things going on here.
Usually, washing machines that are run mostly on cool washes, and/or with greater amounts of powder or fabsoft than the makers recommend, will get a sludge and slime buildup composed of old soap and softener. Mildew and bacteria live on this and stink. It can be removed by doing a periodic maintenance wash with NO POWDER OR SOFTENER at the highest temperature. A Hot White Cotton wash is suitable. Put in white cotton towels if you have them. If the machine foams up, you will know it is doing it with the residue of old soap sludge that has been dissolved by the hot water. Do it again until it stops foaming (this means you have no soap sludge left).
A rarer problem is that if you do cold washes and have greasy washing, for example if you use a lot of bath oil or body lotion that rubs onto towels and sheets, you will get a sludge of emulsified fat inside your machine. Again, a HOT wash will clean it out, but you need to add powder. Ariiel is good as it is quite aggressive. Again you can put your white cotton towels in to save wasting water and energy on an empty machine.
Bleach and vinegar will have no effect on soapy or greasy sludge.
Bleach will temporarily kill bacteria and mildew; but if you do not do a hot maintenance wash, the sludge will still be there so it will quickly be recolonised and start to stink again. The hot wash kills bacteria and mildew anyway.
Vinegar will remove limescale, but this will not be in the tub, it will be coating the heating element. You can also use Calgon or similar to prevent limescale (or buy a water softener, or move to Birmingham). There is a view that the money and effort you spend trying to prevent limescale is greater than the infrequent cost of a repair. Limescale is nothing to do with sludge and mould.
Remember to clean out the pump filter from time to time. This is described in the machine instruction book which you have not read since the day you bought the machine.