Tenant unco-operative when repairs appointments neeed to be arranged

My tenant has reports a couple of important problems that need to be fixed by workmen but when I try to arrange appointments the tenant is being difficult.
Does anyone know what the LL rights are to use my own keys to take workmen to fix things if the tenant cannot be home.
My tenant has told me I may not enter the flat using my own keys even if I have given a few days notice that I need acces to fix things. The toilet is not flushing away and I want to get a drain company to attend to a possibly block soil stack. Also, the new electric heaters are not working and my electrician need to investigate why and possibly replace them if they are defective.
I will be grateful if you can let me know my rights and obligations regards access.
I signed the standard Openrent AST with the tenant.
Thanks.

The tenant is entitled to quiet enjoyment. The following quote has been copied directly from the How To Rent guide and states the LL must, "Seek your permission to access your home and give at least 24 hours’ notice of proposed visits for things like repairs. Those visits should take place at reasonable times – neither the landlord nor the letting agent is entitled to enter your home without your express permission.”

It may be the case that the tenant "is working all the hours that God sends.” You could ask the tenant if you could pass their number on to the tradesman directly, so that they can arrange a suitable time for themselves. Let them know that repairs need to be dealt with promptly to prevent them getting worse. If they are wilfully preventing the LL honouring their obligations as a LL I would serve a section 21.

You have rights of access which are in direct opposition to the tenants right to quiet enjoyment. Neither right really trumps the other, but a court may well find you guilty of harassment if you enter when the tenant is not present after they have specifically denied you permission to do so. Make a diary note of every declined date and the declined permission to go alone and keep any written evidence so that the failure to repair cant be used against you. You need to keep trying though. If any of the issues are likeky to damage the property, you could get a court injunction to force entry, but this is not a straightforward process.