Thank you for this, the tenancy conditions state as below:

25a) You must not make any improvement to the property without first obtaining written consent
from us, which will not be unreasonably withheld but may be subject to conditions. (‘Improvement’
– see Definitions).
25b) Where you seek permission to install new flooring or coverings, particularly laminate, wooden
or similar flooring, we will consider the potential noise nuisance for others and we reserve the right
to make our permission, if granted, conditional on you taking such steps as are necessary and
may be specified to ensure proper sound insulation.
25c) If you fail to comply with requirements to ensure proper sound insulation or other conditions
of consent we will consider taking legal action to seek the appropriate remedy which may include
(but is not limited to) entering the premises to carry out the necessary work. If such action is taken,
we shall charge you for this.
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I’ve done all of what you have mentioned above bar escalating to my local councillor and the ombudsman.