If you're a regular traveller and like Accor hotels then the Accor Plus membership is a good option. It's been refreshed recently and the main benefit is if you book two nights or more, you can get one night free (the most expensive night). You get two of these, plus 15% off above your usual member rate, discounts on dining (never used) and higher status which can give you late check-out options. I've used it to book a few nights at the Sofitel for the first time to end my upcoming trip (I'm curious to see how it compares to the Hyatt). I've found that Accor Plus has more than paid for itself, but of course you need to run your own numbers to see if it benefits you. 

I have stayed there a few times over the years, most recently last August.  It is 100% LB friendly and there is no guest charge, just ensure that your advance reservation is for two guests. Any security guards you see will just smile and wave at you and your LB. It has entrances on both Soi 2 and Soi 4. Soi 2 entrance is the lobby and Soi 4 entrance is through a small parking garage. The smart move is always depart the hotel thru the Soi 4 entrance and then return through the Soi 2 entrance. Soi 2 has very little traffic compared to Soi 4 and if you utilize taxis or tuk tuks, it is much faster using 2.  They have a large rooftop pool that has no shadows and there are always plenty of loungers available. If you walk across the skybridge to the other hotel tower, you will find a nice rooftop garden that attracts loads of hummingbirds. It's a pleasant surprise and a real gem.  I have never tried their restaurant, but a couple of minutes away on Soi 4 are Swan and the Dawin hotel's restaurant, both of them modest but outstanding places that punch above their weight. The Dawin's restaurant is directly across the street from Why Not, so while you eat your dinner you can check out the available girls at WN.  It's not fancy, but it is spotlessly clean, quiet and the rooms are large. It's good value for the money, less expensive than similar hotels like Adelphi Suites but its location is on the periphery of the red light district and the LB bars take a bit more time to travel to. 

Nope ... directly on https://all.accor.com

Agoda?

I've booked (a while ago alreafy) the Mercure for my upcoming trip, end of March. Costs about 100 Euro (87 GBP) per night