Thanks everyone.
Yeah it has been a struggle shaking them off, especially as SHE kept mithering other people and asking them what is 'wrong' with me. (Because apparently I have 'not been myself!')
Like for instance, when I bumped into her (let's call her Sue,) on the Aldi car park (around April this year,) which is 2 minutes walk from the doctor's surgery, she tried to strike up a conversation. I said 'I'll have to go I have a doctor's appointment (which I did.) 'Oh,' she said, 'shall I come with you and wait with you?' I said 'errr no, coz I need to speak to the receptionist about something personal.' 'It's OK I won't listen' she said (grinning.) 'Err, no sorry, I need to go the loo as well as I have a bad tummy, so I will see you around.' Then I bolted. A similar thing happened a week later when I was in town and was meeting my husband who had been at the dentist. 'Can't stop,' I said.
And when she has seen me in passing she has said 'we will have to go for a meal, when are you free?' 'Oh, I think we are really busy for ages now,' I said.
Then out of the blue, (around mid May,) another friend of mine who lives down the road, (who knows her too,) called me randomly for a 'chat' to see if I was OK. 'Yeah I am fine' I said 'why?' She didn't say much and just said 'oh just making sure everything's fine.'
Then after a few minutes of chatting, she said 'Sue said she hasn't seen you for ages... is everything ok with you and her?' And I said 'I don't know what she's on about, I saw her on Monday on Aldi car park and had a chat with her then, AND me and my husband saw her and her husband the week before outside Boots in the high street and chatted for a short while, five minutes or so.' (which we did - just to be polite, like we would with anyone we know...) 'Oh, said the woman, she never said that, she said she hadn't seen you for ages...' I just changed the subject then.
Then some weeks later, this woman asked me round her house for a coffee (she rang me,) and I said 'yes ok thanks.' Then she said 'shall I ask Sue as well?' 
I actually said 'maybe next time? It would be nice to just have a chat to you; I haven't had a good chat to you for ages.' 'Umm, ok then,' she said. I'm not gonna lie, I was royally pissed off about this; I thought 'why the F is 'Sue' even being mentioned?!
Then when I went round, after about half hour of chatting, she proceeded to ask me if I ever go to Sue's house anymore. I thought FUCK THIS, I am going to put this to bed right now! ... I said 'no, and I never did really... It's just that we moved here at roughly the same time in 2014 - (me a few weeks before,) and she kind of latched onto me, as I was new too, and she asked us out to the pub (with our husbands,) and for a meal a couple of times, and we went to be polite, and because we were new. But after a while, me and my husband met other people and sort of drifted from them a bit. Nothing personal, we just don't have anything in common really, and there's quite long silences sometimes, and we feel they may be better off making new friends....'
The woman looked wide eyed and said 'ohhhh, well yeah it happens I guess..... I mixed with a few people when I moved here, who were also new, and didn't stay in touch much when I met other people...'
So she seemed to understand and hasn't asked since. and 'SUE' has not called or texted since. RESULT.
However, I was really pissed off at being 'grilled' and asked why I have not been bothering with 'Sue' as much. I am a middle aged woman and don't need to be grilled, or asked, or told I need to contact someone more!
Me and my husband have seen Sue and her husband a few times since (in town,) and have been polite and said hello, but since I told this woman what I told her (when I went for a coffee,) Sue has finally stopped saying 'come for a meal' and 'when shall we meet up?' (So I don't know if the woman told her what I said, or gave her a polite, edited version of it!!!) And although she did walk past our house and stare in 3 or 4 times though July/August (in the hope of 'catching' us probably!) she hasn't bothered us since. (THANK FUCK!)
But yeah, I agree; as you all say, sending a Christmas card is sending out mixed messages. This woman made my life miserable badgering me, hounding me, asking me to take her places, badgering my husband to do stuff for her and her husband, and not responding when I didn't give her an answer she wanted, and just being a bloody nightmare.
For example, she would text 'We are just coming for a walk - we will pop in and see you in about 10 minutes.' 'No don't please,' I texted back 'as my hubby is a bit unwell and he needs some sleep as he has along day at work tomorrow.'
Now most normal people would text back and say 'oh, I hope he is feeling well soon. Maybe another time.' But she sent NOTHING back. Because I wasn't saying what she wanted to hear, she didn't respond (to show how annoyed and offended she was!)
Some people might say my text back didn't 'require' a response. But that is not the point; it would have been POLITE to acknowledge it. It's called conversation. If someone said to me 'it's freezing out there,' technically that is a statement and doesn't require a response, but it's bloody rude to not respond. Just say 'yeah it is bloomin' cold!'
She should have answered, with 'Hope he is ok,' and I would have replied with 'yeah thanks see you...' IMO anyway!
Anyway, earlier in the year, when she texted me a few times, I stopped answering her at ALL. I thought 'well you don't answer me most of the time, unless I am saying what you want to hear.... so fuck ya!'
When she saw me a week after she texted once (earlier in the year,) she said 'did you not get my text from the other day?' I said 'yes I did, but I thought I would wait to see you to give you an answer, because I wasn't sure if you would get my text, as there are quite a few I have sent you that you haven't responded to; so I assume you are not getting some of my texts.' She just looked a bit 
... but what could she say to that? Nothing!
But yeah, the original point of my post is still not resolved, but my husband hasn't mentioned it since. I am just really worried that if I say 'I am NOT sending them a card,' he will sneakily write one and pop it round. I have no idea WHY, because he couldn't stand them, so why the F does he want to send them a damn card?! When I said 'WHYYYY? Why do you wanna send them a card?' he said 'to show there is no hostility!' But we are showing that by saying hello when we bump into them in town. Why the F do we need to send a Christmas card? No fucking way are they getting one.
My husband confuses me; he found them irksome and annoying, and rude and obnoxious, like I did.. I mean, they were always late, they were self absorbed, and they were a pest, and he seemed to be as glad to be rid of them as I was.
Sorry for this uber long post. Feels good to get it all out. thanks for listening. 