I get the same all the time now. I say to them "If you want an
actual periodic inspection carrying out with a professional and unbiased report that's worth the paper it's written on at the end of it, this is the service we offer. We charge what we charge because to do the job properly and without cutting corners we allow a full day (half day for a bedsit or small flat) for a fully qualified and time served electrician to carry out the report. If all you want is a piece of paper then you can easily find a short course electrician, commonly known in the trade as a five week wonder, that will drive by the house for fifty quid."
If I'm being totally honest, I reckon that speech works between 70-80% of the time.
I'm also amazed at how many commercial PIRs I pick up simply because the others that quote per circuit over the phone simply fail to mention any form of pre-inspection survey!
"Pre-inspection survey you say? No one else has said anything about that?!"
I then calmly explain to them that without a survey being carried out prior to an inspection, how am I able to meet with them and discuss issues such as the scope of work required? How am I able to ascertain whether any circuits need to remain energised or whether any special arrangements need to be made in order to complete the work? I tell them that I need to be able to see records of previous work undertaken and the results of any previous testing. I tell them that I need to see the installation to ensure that I can put any safety measures in place if needed and that a small amount of preperatory inspection may be needed to identify circuits and highlight any items that may need a deeper degree of inspection, all in order to help with determining sample percentages.
I let them know that once a survey has been carried out, only then can I provide them with an accurate price.
"Oh yeah" they say... "There's a lot more to this than I thought" they say...
"When can you do the work?" they then normally say!
Edit: I mean this in a totally non-arrogant way, but by highlighting your strengths, you expose the weaknesses of others, thus meaning you can land more work as a result. If they're still only willing to pay peanuts, then they're more than welcome to their monkeys!