If you want to sell in the UK, finished products must meet EU standards. You need to certify this, not the suppliers of the components, either by constructing the technical file yourself or by outsourcing the certification process. Buying parts with CE marks on does not make the finished item CE-marked, you have to do this for each type of product you make. Therefore you must research all applicable directives for your product (e.g. Low Voltage Directive) and any constructional standards that the marketplace expects, and determine suitability of components to meet those directives and standards. Only then can you say whether a component is suitable.
FWIW, lighting products for EU sale are normally fitted with 0.75mm² flex. Double-insulated appliances often have the popular flat sheathed 2-core HO3VVH2-F, 300/300V rated and made to IEC60227-1. Larger CSA is not necessary for normal usage, smaller is generally non-compliant. But if you had special temperature, mechanical or flexure requirements this cable might not suit, and only you can determine that.
Unless you have a fully equipped goods-inwards test and qualification facility, I'd agree with the above advice and source within the EU. I have recently been screening out non-compliant parts even from reputable manufacturers where their Far-East subcontractors have realised they can get away with substituting un-approved but similar products at the final stage before the customer takes delivery.
Even in the UK where the plug is fused, in real life most people only use 13A replacements so I'd suggest you don't go below a flex size of 1mm sq regardless of how low your load current is for these reasons. Also 0.75 and 0.5 mm sq flexes are very prone to accidental stretch damage.
I don't know what you're doing to your flexes over there Marvo, but here in You-Rope 0.75mm² is the most common cable for small appliances and lighting. I've just checked about 30 double-insulated electronic goods in my workshop and every single one is 0.75. 3-core appliance cables are a mix of 0.75 and 1.0, both may be fitted with 13A fuse unless used as extension cables that can be overloaded by the user.