I am currently hired as a Warehouse Colleague by a large Logistics company in the UK. After finding out about my technical background, qualifications and hobbies, they seconded me into the IT Department where I went on to become Lead Software Engineer for a very large and successful project. The software was rolled out across our UK sites and then re-branded and used as a "Gift / Perk" for several of our key partners, so it is now being used in 7 very large companies, including supermarkets and a car manufacturer.
I wanted to use this experience to get a better job, as I am still officially only a Warehouse Colleague and still only being paid minimum wage, despite programming bespoke software from scratch. (With no possibility of a promotion here as a programmer is a nice extra for the team, rather than a necessity).
I used the advice from here that I should write my CV so that it states my official title and then a title that best represents what work I was doing. On my CV I put "Warehouse Colleague (Systems Support / Software Development)" and thought that would be the end of it...
I was turned down for a job using this CV, when I contacted the HR Department for the company to enquire why I had been turned down, they said that they had called my current employer and had been told that I was only a Warehouse Picker and had not performed any other roles at the company. At first I believed that this was simply an oversight by our HR, but when I approached them I was told that HR do not keep track of secondment positions and will not inform potential employers of anything that I do during secondment. Officially I am in the warehouse picking stock, so that is all that they will tell anyone.
Now I'm stuck. If I can get an interview then I have several documents, emails, letters and printed guide-books for the software, all with my name on as the software developer. As well as several code examples that I know like the back of my hand. Problem is that I can't get an interview because anyone contacting my employer will basically be told that I am lying.
Is there any way that I can use my experience on a CV, despite HR shooting it down? Is there any polite way that I can make it clear to potential employers that my current employer will not be helpful?
Thank you all for your time, I look forward to your answers.