Two months ago I paid my deposit to the tour agency via PayPal. No fees, no charges, no nothing for anyone.

This is something I dont think has ever come up over the years so its either new or never worried anyone to the point where they'd complain here.
Cheers for all of the comments - you're probably right - it is too small an item to bother writing about and apologies to everyone for this. My posting was more a request for advice and comments.... Even before posting my question, I realised that the Tour Guide I am travelling with probably wasn't aware of the extra charges and so was taken by surprise - showing up the initial teething problems / hidden costs that pop up when setting up a new business.
The reason I was getting more worked up is that in all the years I have been sent money from abroad, not once have I as an end user had to encounter fees at my end. Surely if you ask your bank to send a set amount you expect that exact amount to arrive to the recipient - is that really so big an ask? If it had been an airline / hotel I had transferred this money to would we still be having this conversation? It would be totally unacceptable, to send less than asked for to a company rather than to an individual. Stupidly I though paying $50 dollars in bank charges this end for sending this sum would prevent any further deductions from the original amount..... how naive I was.
Anyways, alot of the comments made me smile...there's really nothing like having a go at the 'bankers' to help let off steam eh? We do it all the time over here in the UK to cheer ourselves up! :D