Mold and the accompaying funky smell is a fungal infection from mold and mildew trapped inside the dreads on the hair strands of well meaning deadheads who wash their dreads far too often and never let them dry completely to the center of the dreads. It is spread by fungal spores not powders. If you are truly worried about mold from living in the damp humid UK, Vicki from the dreadlocks shampoo site makes a product that uses natural plant based fungicides that actually kill the spores (the hardest part to get rid off in a mold and mildew infection). Its called Rot Knot Mold Eliminator and you use it sparingly, once a month for preventive maintenance. With the exchange rate of pounds to dollars it should be very inexpensive for you. Here's the link:
The best way to prevent mold & mildew is to make sure you wash less frequently then you used to. This is more important the more your dreads mature and go from loose hairs to knotted ropes of hair. The thicker and fatter the dreads, the more time they will need to dry. The general rule of thumb is three days. The outside hairs will feel dry to the touch within a day but it is the deeper hairs within the center of the dreads that will be the most prone to mold and mildew as they retain moisture and are never exposed to sunlight.
As for workplace cleanliness I hear you loud and clear. I work in healthcare, understandably one of the worksites most prone to infections. We worry about fungal, viral and bacterial contaminates getting onto our skin, hair and as well as into our respiratory systems. For protection we wear protective clothing and equipment as I am sure you do as well. For longer hair specifically use a Scrub Bouffant that will cover your head completely from your forehead to the bottom of the nape of your neck. Make sure it is long enough to fit your dreads into. Try healthcare scrub sites, you'll find a lot of different patterns and colors that will look professional yet fun as well if that's your style. They should be of a nonporous non-woven material like polyester as they will offer better protection then cotton ones.
As for cutting dreads, this is the most drastic and final step. If you were following the nazarite vow this is the final part of the vow. Once the allotted dedicated time had passed they would finally cut their hair and offer it as a burnt offering at the temple. This is the thing with dreads most who do not have dreads do not understand, even when you begin your journey it is not completely clear. Dreadlocks are very spiritual, it doesn't matter what your religion is. The longer you walk on this path the clearer it becomes. The letting go of appearance and vanity, this is the one of hardest steps in the dreadlocks process. Be patient and learn those lessons that the journey will teach you.
You are coming upon the hardest part of the journey. Once the newness and excitement has left, you are faced with the daunting realization that it will be close to a year before they start to resemble proper dreads. Do not lose hope, we have all had those same doubts. Be patient and strong, have faith that eventually the process will begin to unfold and your dreads will mature. I find that posting pictures here has helped a lot. I don't see the progress day to day until I post a pic and the progress becomes very apparent.
As for shrinkage, this is a very good sign. It means your individual hairs strands are maturing by tangling, knotting and weaving themselves into the properly strong rope like structure of dreadlocks. Your hair is growing all the time, so don't worry about the length never coming back. With dreads they are more like branches on a tree, they will grow and develop slowly but surely. Also you won't loose as much hair because the majority of them will be woven into the dreadlock. On average most people loose 127 hairs PER DAY. So don't fret over shrinkage, if anything it should be encouraged. Look at the locking up shampoos from Vicki on the dreadlockshampoo site. I've used all the different ones, Jamaican Mango & Lime, Knotty Boy, Dr. Bronner's. Nothing works better for maturing dreads then the artesian made locking up liquid shampoo from Vicki.
Finally if you still want to do away with them you do not need to cut them. I have friend who him and his wife had very mature and long dreads who decided to remove them before the birth of their daughter. It took a whole day and many washings with a conditioning shampoo and conditioner followed by extensive combing. The ended up using an entire bottle of conditioner each, but in the end all the tangles and knots were all combed out. Have friend or family member help out, and be prepare to see a lot of loose hair on the floor and bath tub. It will seem like your loosing more hair then you are saving, these are hairs that you would have lost anyways over time if they had not woven themselves into the dreads so don't worry.
In the end it is your choice, I hope that you keep them and keep us posted.