Price: Given the location where you are located, I would advise you to start with a low price: 120-130 pounds per hour.
When you start everything is always more difficult, especially marketing. If you start at a higher rate and have no customers, this will be disheartening. If you are forced to lower your prices, it will be even more discouraging and some customers will notice and make ironic comments. If you start at a lower rate, build self-confidence, see how things go and then raise your prices.
Hotels: Choose three or four star hotels. To find out if these hotels use keycards, you can simply call and ask two or three questions ...
Photos: Like the other girls said, don't try to tamper with your photos with Photoshop. Men are not only attracted to your physique (even if it is the main thing), they are attracted (and repelled too) by your personality as it appears in your advertisement.
GFE ?: GFE is much more popular than Dominatrix, especially if you are a young woman.
Lesbian: The market is almost nonexistent if you want to find lesbian clients. I think this is something that depends on evolutionary biology: very few women are willing to pay to have sex with a female or male partner!
Questions: Search the SAAFE forum using the "Search" tool at the top right. You can also start a thread for each specific question. This is better than doing a thread where you ask questions on a lot of different topics.
Good luck!