Hi Mike,
Thank you for the post.
First is your machine under warranty? All Jura coffee machines have a 2 year warranty.
If your machine is sitll under warranty I would recommend you to give Jura a call directly so they can arrange to pick up your machine and repair it for you. Jura's number is 0870 481 0049
If your machine is not under warranty you may have to get it repaired or serviced, again only Jura is able to offer repairs, so please try the number above.
I would suggest that you remove the frother, take it to parts, thoroughly clean it - you may want to use a paperclip or needle to clean up the steam pipe.
I would also recommend that you descale the machine - you can buy descaling tables from here: http://www.fairfaxcoffee.com/Items/Coffee-Machine-Accessories/Jura-Accessories/Descaling-tablets---9-pcs.aspx - £13.30 for 9 tablets which should last you around 6 months.
If none of the above works please do give Jura repair centre a call and let us know how you get on.
Good luck!