Unless there is an exclusion somewhere I haven't seen the Land drainage Act 1991 below governs yours and your neighbours ditches
23Prohibition on obstructions etc. in watercourses
(1)No person shall—
(a)erect any mill dam, weir or other like obstruction to the flow of any ordinary watercourse or raise or otherwise alter any such obstruction; or
[F1(b)erect a culvert in an ordinary watercourse, or
(c)alter a culvert in a manner that would be likely to affect the flow of an ordinary watercourse,]without the consent in writing of the drainage board concerned..
Watercourses’ Defined under the Land Drainage Act 1991
as “all rivers and streams
and all ditches, drains, cuts, culverts, dikes, sluices, sewers (other than
public sewers within the meaning of the Water Industry Act 1991) and
passages through which water flows
And you have section 28
28
Orders requiring the cleansing of ditches etc.
(1)Where a ditch is in such a condition as—
(a)to cause injury to any land; or
(b)to prevent the improvement of the drainage of any land,the [F65appropriate tribunal], on the application of the owner or occupier of the land, may if they think fit make an order requiring the person or persons named in the order to carry out such remedial work as may be specified in the order.
(2)An order under this section with respect to a ditch may name—
(a)any person who is an owner or occupier of land through which the ditch passes or which abuts on the ditch; and
(b)any person who, though not such an owner or occupier, has a right to carry out the work specified in the order or any part of it.
(3)Where an order under this section names more than one person it may either—
(a)require each of those persons to carry out a specified part of the work specified in the order; or
(b)subject to subsection (4) below, require all those persons jointly to carry out the whole of that work.
(4)Where the [F66appropriate tribunal] make an order requiring persons jointly to carry out any work, the Tribunal, without prejudice to those persons’ joint liability, may, if they think fit, specify in the order the proportions in which those persons are to contribute to the cost of doing so.
(5)In this section—
“ditch” includes a culverted and a piped ditch but does not include a watercourse vested in, or under the control of, a drainage body; and
“remedial work”, in relation to a ditch, means work—
(a)for cleansing the ditch, removing from it any matter which impedes the flow of water or otherwise putting it in proper order; and
(b)for protecting it.
Any information provided is not legal advice and you are advised to gain a professional opinion