Personally I’d also contact a spray/powder shop. For a basic job you’d be looking at about £50 which you’d only just be below buying stuff to do it well yourself and you’d save a lot of hassle.
Nitromors became rubbish when they removed the Dichloromethane. As it was made illegal for consumer use in the EU you won’t find products containing it anywhere. From my experience there now appear to be two sorts of products on the market. Nitromors types which contain Methanol and a range of powerful solvents and then those based on Acetic acid. Nitromers still works the best from the ones I’ve tried – even compared to some I’ve knocked up myself.
Heat gun might be as effective. for a DIY job.