I find the first image a little muddy and underexposed, and the second is lacking contrast. I like the compo though.
If you'd like to practice converting to B&W, one suggestion would be to shoot in RAW + B&W jpeg in camera. Post the SOOC jpeg, and upload the RAW file to a new post. Then invite people to convert the RAW into a pleasing B&W. The one(s) which look most pleasing to you will be the one to emulate. The poster can then tell you what they did to convert to B&W.
Thank you kimchi for your comments and suggestions. I've treated myself to Silver Efex, so I've been getting to grips with that and having fun with it.
I use LR4 and PS6, does Silver efax work with these or is it separate?
Yes, Silver Efex works with LR as a plug-in. That's how I'm using it.