Vintage Horticultural and Garden Machinery Club

Hi – Newbie here!
Hope this is the right place to post a request for ID help for a vintage electric strimmer.
I’ve just inherited a mains electric strimmer from a newly deceased relative and it is in good working order, but has run out of the plastic strimming strip. Being new to the world of strimmers, I thought it could just be a case of getting some of the plastic “string” and winding it onto the existing “bobbin” (sorry about the terminology ignorance!), but it seems that any replacements come in the form of cartridges. Sadly, there are no markings indicating a manufacturer or model number, so I have no idea what to search for. Hence, I’m hoping one of you nice people (gardeners are always nice people!) could help me out with an ID.
There is a label showing that it was originally supplied by a company called “M & OW Centre” in Louth (too far away for me to travel), and the guy that answered the phone said he bought the company 6 years ago and has no idea of what make of strimmers were previously sold.
I suspect that the strimmer was originally purchased by the deceased lady’s husband who died around 35 years ago, so I have no means of finding any further information about it from the previous owner.
I really struggled to get the black cap removed and the cartridge/spool/cassette “thing” is white plastic with a non-removable white strip all round to keep the “string” in place, with just a small slit where each emerges. Sadly, I don’t have a photo of that, but I’m attaching the 2 photos of the strimmer itself that I do have.
I am sincerely hoping that I don’t have to scrap this just for the sake of a lack of a length of plastic string, so please help if you recognise the make and/or model of it or if you could offer advice as to how I can prolong it’s life (I’ve only used it the once!).

Thank you in advance for any assistance you can offer.