As with most retail jobs,I imagine it would be low paid,never asked of course,but would expect under £10 hour!
For a retail job your better looking at vacancies at Aldi - they’ve got a big expansion programme under way with new stores opening Yes they work you hard but for the right staff, good job prospects and training opportunities leading to more senior positions Industry leaders in regards to pay, even for the humble but much needed shelf stackers (my son, part time )
All money is good, but the average trade counter assistant does not get much of it. I would think most are on a little above minimum wage if working for one of the big chains. Independents probably pay more as the owners are more likely to recognise the value of a knowledgeable individual, but Margins for such outlets are probably tighter than the big chains.