Andrew, I'm afraid you have to accept that paperwork supplied with a model means nothing as at some point in the models life the paperwork has become lost and the wrong ones attached to your plant. You may have even bought it from someone who genuinely believes that he has sold you a Hemmens Caton but the bottom line is that it isn't and I'm afraid a Caton twin is worth a lot more than a Wilesco so you have to now be honest when considering what to do with it.
If you decide to use the model, and why not it's a perfectly good model to cut your teeth on as regards a first steam plant, then you should do a bit of reading as regards how to look after and operate such a plant and then enjoy yourself at the pond. As I've said above the engine should be run in first and then you can go onto putting some steam through it. The safety valve must be tested long before you even consider doing this so I would firstly put a bit of time into running in the engine and getting to know how it all operates.
I'm afraid a lot of people buy a steam plant and expect it to be as simple as an electric motor but unfortunately you need to put a lot more into it than that. Having said that the rewards to me anyway are far greater so well worth the effort but you do need to have an idea of what you are doing because at the least you could damage the plant and at worst you could hurt yourself.
The articles I wrote for Model Boat Magazine are all aimed at the first time steamer so give just the sort of guidance you are looking for. If you subscribe you can access all six articles on line so it's a pretty useful thing to do.
I get the impression that you are trying to run before you have learnt to walk and are now getting impatient with the model. I can assure you that is normal and you have to reajust your thinking from electric to steam and slow down a bit! Run the engine in, test the boiler and test the safety valve, test the engine on steam on the bench and only then, when you are confident in the fact that it is all going to work, do you put it in the water. You need to then get a feel for how much water the engine is going to use, how much gas it's going to consume and how often the engine lubricator needs filling before you venture too far away from the bank.
If after all this you decide to give up on it you will have missed out on a very satisfying and rewarding aspect of model boating, which is a shame, but you will have to sell it on as a Wilesco plant and not a Hemmens Caton. You may as well advertise the instructions seperately as they are of no use to this model at all. I would stay with it because when you see the point of it all the bug will bite and you will start to really enjoy it, although of course youmight have to accept that you may never see the point!