I worked in business analysis / industrial engineering for warehousing and logistics. The following are what I find most helpful, for most businesses:
A) Inventory, space, time, wastage --efficiency improvements
Vigorously reduce inventory -- the number of skus, packaging types, and sheer variety first, followed by the quantity. In terms of quanity, try have just enough to fill this month's orders, to sell the inventory before you you have to pay your supplier for it.
To do this, YOU should "dump" to clear out under-performers, non-fast moving stock, over buys, etc. I would start by sorting your product line into thirds -- top movers, middle, bottom -- by volume and then by profit. Dump the bottom third unless they are essential to selling other topline items. Think about dumping half of the middle group, too. Sell at a steep discount - any money now is better than no money later when you have to put it into a rubbish bin and pay to have it taken away.
This literally frees up space, allowing you to downsize your rent or to simply move your production line much faster. So much wasted energy and money and time is related to inventory, and most of it is often dead stock, or nearly so, that you keep driving around in the warehouse.
B) Single piece / small batch flow -- Try to almost eliminate WIP, setting items down before complete, working on stock before an order is in, etc. WIP only works for highly seasonal companies (think patio furniture, turkeys, A/C fans, etc.).
C) If you have trouble keeping employees, have you looked into hiring those that do not speak the most common language in your area? New immigrants, in other words. If you can start to hire from a single specific language group that is common in your area, but not the local language, then you are more likely to get better educated people, happy for FT shifts and resistant to moving on. Provide benefits and consistent schedules. Hire an interpreter for your HR role, and write out instructions in dual languages. For Poland, right now, I would also try advertising in England to see if you could get anyone interested in moving back. Give a bonus if they stay for 2 years, etc. Consistent staff that show up to work are a huge benefit in this industry. And a huge nightmare in safety and supervisory time if it is not working out / turn over, etc.
D) Differentiation strategy. Some customers highly value the ability to order today at 4pm and have it shipped out before 9am tomorrow. It is not easy, but with a streamlined efficient facility can be done. I have worked with two very successful businesses that based on this strategy. e.g., last minute and late orders with very fast fulfillment cycles. They did not charge more, but got more orders and consistent customers. If you get it right, it hardly costs you more than a 24hr cut off time.