I don’t know about UK standards specifically but I’ll give you my 2-cents worth.

1. The dimensions on the right hand view are too crowded. Spread them out. The extension and dimension lines and arrow heads should never overlap the dimension text under any circumstances.
2. Never dimension to hidden lines except under the extreme circumstances. Like never! You’ve placed many hole note leaders to the holes in the main view where they are shown hidden. These leaders should be in the correct views where the holes are shown with solid object lines.
3. Some items are undimensioned. Like the m12 x 25 hole centered in the upper view.
4. Maybe this is the way the customer wants it but I would avoid chain dimensioning because of how quickly tolerances can stack-up. The only way to avoid that is with specific locational geometric tolerances. But still, layout for this part requires a lot of math having to add all those dimensions together. It’s generally poor practice and most shops are going to hate it.
5. You have no centerlines on your holes. And you have not tied those centerlines together to clearly denote what holes are on the same centerline.
6. The scale/resolution of this drawing is such that you can’t tell the difference between the plain holes and the tapped holes.
7. You don’t have a quantity of the holes called out.
8. Leader lines should cross open territory. They should never cross or interfere with other intersections of geometry, dimensions, leaders, centerlines, etc. For example the 18mm hole leader crosses exactly over the intersection of the adjacent extension and dimension lines. Move it so it only crosses one of the dimension lines. The m12 hole note text sits directly on top of the 160 dimension line. Move the 160 dimension up so the hole note can sit by itself and not cross anything.
9. Dimension extension lines should clearly extend from the profile of geometry if possible. For instance: the 140.2 dimension in the bottom of the main view isn’t necessarily wrong but it it would be much better in the top view. The 27.3 dimensions should be in the right hand view.
10. That same 140.2 dimension should only go to the first of the in-line geometry in the bottom view and not cross over at all. (Another reason it should have been in the top view to begin with.)
11. The top view is spaced too far away.
12. You have chain dimensions stretching the full length of the part in the main view. You also have a dimension for the full length of the part. This is known as superfluous dimensioning. (Too many dimensions.) At least one dimension in the chain or the full length dimension MUST be a reference dimension.
13. Some of the chain dimensions are missing arrowheads. Probably because the dimension is too short for them to fit.
14. You’ve shown holes threaded all the way to the bottom of the drilled holes. That requires a bottoming tap and a lot of work. Probably not what’s required 99.99% of the time. Your hole notes should specify drill depth and thread depth. Don’t leave it up to the machinist because he won’t know. You should know and it needs to be on the drawing. Generally the drill depth should be deeper than the thread depth an amount equal to the drill diameter. If you don’t know how deep the threads need to be, find out from the designer. Don’t guess!
15. The spacing and placement of dimensions should be consistent and pleasing to the eye throughout the drawing. The dimensions above the main view are crowded up next to the geometry. The dimension below the view are spaced far away.