The exchange rate has been around £1 = $1.50 in the last couple of years, although it's dropped nearer $1.40 in the last few months.
Average pay is a bit of a tough question for me to answer, because I'm only out on wiring work less than half my time and as most people want an estimate before any work is done, I tend to price each job separately.
I usually take cost of material plus about 10% to 15% to cover expendibles and contingencies, then figure my labor against my estimation (guess?) of the hours involved. I reckon a reasonable average for my jobs comes to around £10 (approx. $15) per hour, more for a one-afternoon job, a little less for an big ongoing job over several days. That's almost all residential, with just one or two light commercial.
With gasoline here costing around U.S.$4.75 per gallon, I'll add some for travel expenses if it's more than a few miles away. (I also tend to bump the price up if it's a particularly nasty job or for somebody who annoys me.) There's a 17.5% sales tax to add on to the final bill as well; customer pays it to me & I pass it on to the government.
I can't honesty say what the other self-employed guys charge as I've never had to call on one
. As for those who are employees, I've seen quoted salaries varying from under £10,000 per year to over £50,000 depending on the company and the location, so it's difficult to quote an average wage. The higher end is most likely industrial work for the big oil/gas plants or similar.
Sorry to be somewhat vague on this, but I just haven't been involved on this side of things enough to know any more details.
Licensing/certification I can be more specific about. As far as pure legalities go, there is no electrical license in the U.K. and anyone can set-up as an electrician with no formal qualifications whatsoever. (And for residential wiring, it is not even a legal requirement to follow our IEE Wiring Regulations, though highly recommended, of course.)
That said, there are several certifications available from trade organizations, and most companies recruiting for a "qualified electrician" would probably demand one. It's also unlikely that a non-certified self-employed sparky would get a contract for a big commercial/industrial job without one.