Hi and welcome to MM Dottyaboutdurham
Just as girls tend to start periods earlier these days, many women are continuing to have periods later as well!!! You are technically still peri meno, so what you are experiencing is normal and can go on for some time.
You've had scans and tests so I wouldn't worry. If HRT is giving more problems than benefits then that may not be your best option either but HRT can help with some of the issues you are struggling with - I'm afraid though, it is about finding a HRT that suits you. The Consultant is recommending Oestrogel but you would still need some progesterone to prevent the womb lining building up and resulting in problematic bleeding. Most oral or transdermal progesterones can bring some side effects e.g. PMT, low mood, cramps etc. If could be a good idea to consider having a Mirena fitted as this could ultimately result in no bleeding at all, would prevent any erratic bleeding and you can use as much gel along as you need.
AS for weight gain - well, I'm afraid when meno hits, we simply have to eat less generally and make sure we get enough exercise. DG x