Huge difference in house rules

There has been a long period with no contact (2 years).
Dad now wants contact and so Mum is helping rebuild this slowly (going well so far).
The problem is that Dad is now rushing way ahead of himself (a trait he''s known by) and talking of the children visiting for overnight stays. Mum is ok with this but in the future as, of yet there have only been 2 contact visits lasting 4 hours each and after each visit the childrens behaviour has been critisised by Dad.
Dad and wifes house rules very strict, Mums very relaxed (apart from usual things, no climbing on sofas etc).
On a Saturday evening at Mums kids treat is watching TV while eating tea (rest of week is at table with no TV etc) followed by bath and then duvets on sofa for movies. You get the general idea.
Dad will not have this. All meals must be eaten at table, bed at 7.30pm etc.
Mum has suggested that WHEN overnights start that Dad relaxes rules (via email) so as not to un-nerve kids but knows he''ll come back and say no.
Visits stopped 2 years ago as kids could not cope with staying in a house where their every move was questioned and they were punished several times a day for doing things that Mum allowed (nothing sinister just things like eating a biscuit in lounge rather than in kitchen).
Whats everyones views?
Thank you.

Each parent is entitled to their own house rules, personally I like the Saturday eating tea on sofa treat.

I do not think you can try and impose each others rules on each others homes. As long as the children understand the rules and understand why they are there they will learn to accept there are some differences at each home (no two families will be the same!)

I agree. Children need to get used to the idea of different places having different rules. Even when parents are together, children are adept at playing them off against each other as rarely do two people agree on everything!
We have very different house rules to my ex and my husband''s ex. Obviously we think our rules are the best otherwise we wouldn''t have them but we have never tried to impose them on our exes.
Dad may relax the rules more when he is more used to having the kids around if he hasn''t been allowed to see them for such a significant amount of time.

I agree. You can''t impse your house rules on the children''s father. What you can do is help preare the chilnre, by explaining that different houses have different rules, and neither is ''right'' or ''wrong'' - depending onthe childnre''s ages you can help them to understand it by reference to different rules about home / school thir house / best friend''s house/ granny''s house etc.

If you think Dad would be open to it you could let hm know what the children''s normal routine is - he may be more open to it is you can explain it as their routine rather than ''the "right" rules'', to help him to undertand what they are used to, but at the end of the day, he is entitled to have whetever rules he wants to at your house. If the children seem confused then you can ask him to let you know what the ground rules and routines are at his house, but make clear that you are not critisising, but wanting to understand so that you can support the children and help the children to learn what the rules are at his.

Happy again - he wasnt NOT allowed to see them..he chose not to.

My son''s best friend lives in a house with (absolutely) NO rules and in our house we have quite a few to keep everything running smoothly. The first time they had a sleepover together it was chaos as he had never stayed in a house with rules.
I spoke to his mum who was a good friend of ours and she talked about her no rules policy on parenting and I told her I needed to have order in the home. She agreed to explain to her son that there were rules in our home and she asked him to please adhere to them. I agreed to let my son join in the chaos when he sleeps at theirs. When her son walks into our home I say "Remember that we have rules here" (He knows what they are at this stage) and when my son goes to their house she says "Remember there are no rules here"
It has worked well for us for years as the kids are clear as to what is expected from them.

Sorry, you seemed to suggest in your original post that contact stopped because the kids were unhappy about the rules. I misunderstood.
However it doesn''t really change the answer to your questions!!