I will be able to share some up to date information on girl friendly accommodation as my plans have changed. I've now managed to move work commitments around and I can have an extended holiday for just over eight weeks. The main consequence is that I no longer need to worry about internet connection. As such, I have changed my Air France flights and will now visit Ghana, which for me is more suited to a longer vacation. I'm still on the same EDI-CDG flight and then a slightly shorter wait until I board a flight to Accra.
The Gambia - I had booked two separate places to stay, Luigi's and Oasis. Both confirmed they are guest friendly. I made it blindingly obvious by initially asking if as a single man it was ok for me to have multiple visitors. When they both replied yes, I then sent a second email asking if they were sure, as I did not want to make any of the staff or other guests uncomfortable. Both replied that this was no problem and many guests had visitors. Both confirmed that the girl must have valid ID, but that this was for my protection. Luigi's added that they wanted to go out of their way to make sure I had a great time - I was in contact with the owner Julie (initially via contact form on the website and then subsequent emails) and she was really friendly. I was also in contact with Therese from Oasis Apartments and she was also friendly, if a little slower to reply. Plenty of mentions on here and other fora for Oasis, which might afford greater privacy whilst also being more affordable for the wallet.
Luigi's is certainly more expensive. I chose here for the period I thought I would be working. They have three back up generators with wired internet and confirmed it would be possible to work from there. It seemed as reliable as you could get in terms of West Africa of course. Luigi's has several different options with regard to price, though iirc the cheapest is something like £40 a night. It is a mixture of B&B and self-contained apartments, with a range of prices dependent on size, amenities etc.
I was quoted D39,500 for a month at Oasis (approx £580 - there is a smaller, cheaper room without washing machine/large fridge at approx £535) but you have to pay your own electricity and the internet costs. I obviously have no idea what the electric would cost but the internet is a flat charge for the month at either 10 or 20Mbs at D2530 and D4000 respectively (approx £37 and £58).
I am sure I will visit the Gambia one day but my future trip report will now obviously be for Ghana, though I don't leave until the end of September. Safe travels everyone.