Garage clearance causing issues?

What do you expect her to do with the stuff? The garage is part of the property demised to her so she is entitled to quiet enjoyment of it and your responsibility is to keep the structure in good condition. I can suggest only two ways of breaking the impasse.

1: obtain vacant possession by evicting the tenant but be prepared for a counterclaim for disrepair, particularly if there is damage to her possessions.

2: agree with the tenant to have the garage cleared and the contents moved to safe storage at your expense while the work is carried out.

My advice is to think about how you would go about the garage roof repair if you were living there. You can then take that idea to the tenant for agreement. It isn’t unusual to have to conduct a repair on an occupied property and a garage is much easier to arrange with tenants than living accommodation. If your tenant isn’t able to move their goods, you could arrange it for them. I would use a contractor who has liability insurance for any damage.

Patch the leak, and leave it.

fully evidenced letter to tenant stating that you are aware of leak and trying to address this as this is your property, but to do this will involve her removing her belongings out of the garage to do so. Make clear you are not responsible for her items and if damage occurs from this point onwards now you know there is a leak as it will be because she is not allowing you/contractor proper access to complete repairs. This is clearly in breach of her TA (quote section etc) and any delay that causes further deterioration of your property as a result will not be because you are not trying to get the issue resolved. Explain she will be personally liable for any further deterioration of the property and all costs accordingly.

Say you will offer to look for suitable removal companies for her if she wants help to get quotes.

Explain that you have legal recourse to give her notice, but state this is not an avenue you wish to go down at this point in time as you hope an amicable solution can be found. State you are open to further discussion on the matter but that you are keen to get the work completed before the winter approaches so it is a matter of urgency that an agreement is made so progress can be made. Suggest that you give her 14 days to come back to you.

If after 14 days might be best to get a solicitors letter out to her, then it looks like you are taking it seriously. Might be the kick she needs.

Thank you for your suggestions. I think I have resolved the situation now.