Good shout. Emailed Autoglym - they reckon Vinyl & Rubber Care ought to do it, too… (I’ll be testing this very shortly!)
I bought Halford’s silicone spray and the straw they supply with it doesn’t even fit the nozzle! 
It will ben,they are just tight.
In these circumstances I put a small bevel, or lead-in, onto the end of the straw with fine sandpaper/wet&dry/whatever.
Alan
It’s gone in 
he he!
what are you like
I’ve just read this thread and it has reminded me of a funny/tragic true story…
In 1989 my father in law was made redundant and managed to find work within a few days. This meant that he now had a lump of cash (ex print worker!) burning a hole in his pocket. He decided that for the first time, he would buy a new car. So a few weeks later he took delivery of a bright red Nissan Bluebird SLX. He was so proud of this car and would be forever washing and waxing it (ring any bells?). One December evening he drove to the club and decided to let my mother in law drive both him and the car home. By closing time there had been a very severe frost and he couldn’t get the key even into the lock, let alone turn it! One of his mates staggered out into the car park and said that he could open the car “No problem”. He walked up to the drivers side door and urinated on to the lock. within 60 seconds of the impromptu defrost, my mother in law was in the car and the engine was started. Now this might sound like a good idea, and it is if the alternative is freezing to death. The down side of this action is that as soon as the car was warm it STANK of stale urine! My father in law put up with this for the rest of the winter and traded the car in the following March. He felt that a summer “smelling constantly of p1$$” was not the top item on his retirement list, knowing that that would probably come later in life anyway!
I’ve used both WD40 and silicone lube spray on locks and I’ve not had a frozen lock today and it was colder than ever last night!
Doors open with ease after using silicone lube on the rubber seals. No worry about it’s effect on the rubber… it’s meant to be used with rubber and plastic. It renovates them too!
And i beat it smells better than gary’s dad’s old car
Did you do your window channels at the same time
Alternatives -
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There used to be a product called “Loc Lube” which you squirted into the keyhole, and it would lubricate the lock. Tried to find it recently with no luck
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For years I’ve used WD40, which supposedly washes away the special grease in the lock mechanism, so once used you have to keep it up. I found a good spray every 12 - 18 months worked well. Again, stick the nozzle into the keyhole.
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There’s probably a special spray lubricant somewhere on the market or Halfords shelves - again, you should be able to find a product that squirts into the keyhole.
I did indeed! The windows were very stiff when I bought the car. Thought I’d have to remove the door card etc. I sprayed the lube onto cotton wool buds and cleaned & lubed the channels. Windows are great now!!! So easy to wind! 
I’m not bothered about WD40/silicone lube clearing away any of the origional lock grease as WD40 is a lubricant anyways. The origional grease in mine didn’t do me any favours in this freezing weather!
I know why mine and probably others locks freeze more than others… mine was just the drivers’ door lock as it’s that lock that doesn’t have a little metal spring loaded slot cover thingy
or the spring is broken, therefore letting in water!
Or…maybe my passenger door gets pi$$ed on as it’s usually next to the pavement and we get drunks going by on a Friday and Saturday night! 
Gary, that Nissan was definitely a winter only car! 
Another down side to this is if you’re standing too close to the door - have you ever got your tongue stuck onto an ice lolly - I’ll say no more…
Honestly officer, I’m just trying to defrost the lock
Not after it’s been wee’d on, no! 