You state on your profile that modelling is a hobby, and I get the impression you would like to be paid from time to time, but you're not thinking of making a full time income from it. This is cool, and plenty of people do this. If I was in your position, I would go for between £15-25 an hour, and part paid, part TF work.
The reason I would say £15-25 working up to topless, even though you are inexperienced compared to full time/experienced models, is that you will probably get this from people that want to work with you, because of your look, or that you're in their area etc. You won't get this all the time from everybody, but if you're doing this as a paid hobby, you can afford to cater to the people that will pay this to work with a model that they want to work with on a paid basis.
If it is also a hobby and you enjoy the pictures, you could also work for a reduced rate, in return for a selection of edited images. For example, £10-15 an hour, and six to ten edited images of your choice from the shoot.
Despite the huuuuuggge controversy that seems to surround models being paid AND getting to use the images on their ports, I have found that hobbyists are often more than happy to pay a reasonable rate, and are often happy to let you use an image on your port, if you ask them nicely & don't take the piss. So as one model to another - ask for a decent (not over the top) rate and hold out for it, provided you've already made your mind up to be a damned good model to work with
As it's not been mentioned if you do start charging for your time. You will have to declare to the tax man these earnings. Also change your status as amateur to professional. Then become a silver or gold member on here to create paid casting calls. Didn't want to be the one to bring reality crashing down around you.
Whatever people are willing to pay I guess.
Some might only want to pay £5 an hour, others might pay more..
£5 an hour?! Minimum wage is £6.08!
OP, charge what you think your time is worth. I would recommend a £20/hour start, then up it if you find people are potentially willing to pay more. You'll have to up it annually anyway because of inflation, and everything else increases in line with that.
I personally charge POA and enter into negotiations with photographers based on their individual needs. I have a basic rate but add to that factors such as how far i would be travelling (I try and include that for everywhere within an hour of me), what i'd be shooting etc. I also take into account whether they're a student etc, sometimes I keep the NUS on-side and offer 10% off rate.
It all depends on what you think your time, look and talent are worth to the client.
Half way there. You forgot to add on "And be prepared to rethink it if noone want's to pay that"
Rates are like recommended prices. If a shop displayed an item for 99.99, it doesn't mean that's it's worth, if they never sell it.