Hi Katie Darcy,
I'm from a company called Caboodle and we've worked with Make UK and their members for the past 10 years on many aspects of employee benefits and employee engagement. One of my contacts there has suggested that I might be able to add some extra information to the area you're looking at.
Although it is good to streamline benefits as far as possible across office based and shop-floor staff, we do often find that different arrangements/benefits/perks are more attractive (and feasible) to different groups. It is therefore quite common to have a core selection of benefits that apply across the board and tailored benefits to each audience. Depending upon how these are communicated and made accessible to employees, you can avoid disgruntled employees feeling as though they are missing out because they are in a different group.
You mentioned flexible working in your message, and this is a significant area in which an employer can improve their recruitment, retention and overall employee engagement. Giving employees the ability to flex their hours and work location (an element of working from home for example), can really help work/life balance and keep valued employees who appreciate the flexibility. Employees with children are the obvious example of those who will put a high value on being able to start work a little later/finish earlier to deal with school drop off and pick up, but we find across the board employees really appreciate being able to work when it suits them (within limits of course, and this is where employers should always put in place robust rules prior to any flexible working arrangements being launched).
Feasibility is an issue with flexible working for shop floor staff in particular, and this is where you may need to consider having 2 separate sets of arrangements that will work for your business. This kind of arrangement is quite common with organisations with these 2 distinct populations.
You mentioned Holidays in your message, and Holiday Trading (or the more popular Holiday Purchase where employees can only buy extra holiday and cannot sell unwanted holiday) is an excellent way to engage your employees. Anecdotally, employers find that Holiday Purchase schemes have little or no impact on overall productivity, positively impact absenteeism levels and are one of the most valuable employee benefits a company can introduce. Robust rules are absolutely essential here, and you may find the admin workload quite arduous if you choose a run a scheme in-house unless you are a very small company.
You also raised employee benefits/flexible benefits, and if like many Make UK members you are male dominated, I'd suggest you consider a Cycle to Work Scheme which consistently works well. Technology Schemes are also very popular with a broader appeal than Cycles, and probably one of the easiest (and admin free) benefits to make available is discounts and offers.
In general terms, what's hot right now in benefits are Health and Wellbeing, Financial Wellbeing and Reward and Recognition, so all are worth considering as part of your project. I also find that many clients find it useful to survey employees to discover what would be appealing to them, or to have an employee group with representatives from different parts of the business to build an overall proposition that works for everyone.
I hope this is helpful!