Blown exhaust valve

Hi all, hope everyone had an excellent Christmas Holidays! Just before the holidays started I picked up my X10 from the shop after having a new drive belt, rear brake pads and disc and also to free up seized rear calipers. All good I was thinking as I was riding home along the dual carriageway when the power started dropping off. I pulled into a lay by and turned off then waited and fired her up again, off we went all good then she just conked out, I pulled into the side and called the shop, thinking the drive belt had fallen off or something similar. They came straight out in a van and took me home then took the X10 back to the shop for investigation. Next morning I get a call saying an exhaust valve had blown. They texted a couple of pictures too. They said they'd do the repairs at a reduced price even though the fault was unrelated to the work they'd carried out. I contacted the seller who stated the warranty was voided because I'd let another shop do the work before contacting them but they did feel bad so would pay half the cost of the valve / seals etc. replacement.
So, I have to wait for the holidays to finish, shop to order and fit new valve and seals etc. I really like this bike and hope that's it for problems, so far it's been in the shop for longer than it's been in my possession.