I am assuming ( and open to correction) that OP has consent of neighbour to lopping\trimming of trees and that it is only the Tree Preservation Order which is of concern. First thing is to establish whether there is actually an order in existence.
OP should:
1. Ask local authority for a copy of the relevant Tree Preservation Order to see what exactly it says. Ask in writing. If necessary, make it an FOI request.
2. If there is a Tree Preservation Order made, ask a professional tree surgeon to examine the Order and also to examine the site to see if the proposed trimming is exempt
I have pasted below Section 205 of the Planning and Development Act 2000 - see subs. 11 in particular.
205.—(1) If it appears to the planning authority that it is expedient, in the interests of amenity or the environment, to make provision for the preservation of any tree, trees, group of trees or woodlands, it may, for that purpose and for stated reasons, make an order with respect to any such tree, trees, group of trees or woodlands as may be specified in the order.
(2) Without prejudice to the generality of subsection (1), an order under this section may—
(a) prohibit (subject to any conditions or exemptions for which provision may be made by the order) the cutting down, topping, lopping or wilful destruction of trees, and
(b) require the owner and occupier of the land affected by the order to enter into an agreement with the planning authority to ensure the proper management of any trees, group of trees or woodlands (including the replanting of trees), subject to the planning authority providing assistance, including financial assistance, towards such management as may be agreed.
(3) (a) Where a planning authority proposes to make an order under this section, it shall—
(i) serve a notice (which shall include particulars of the proposed order) of its intention to do so on the owner and the occupier of the land affected by the order, and
(ii) cause notice of the proposed order to be published in one or more newspapers circulating in its functional area.
(b) A notice under paragraph (a)(i) shall be accompanied by a map indicating the tree, trees, group of trees or woodland to be preserved.
(4) A notice under subsection (3) shall state that—
(a) the planning authority proposes to make an order preserving the tree, trees, group of trees or woodlands,
(b) submissions or observations regarding the proposed order may be made to the planning authority within a stated period of not less than 6 weeks, and that the submissions or observations will be taken into consideration by the planning authority, and
(c) any person who contravenes an order or, pending the decision of a planning authority, a proposed order under this section, shall be guilty of an offence.
(5) The planning authority, having considered the proposal and any submissions or observations made in respect of it, may by resolution, as it considers appropriate, make the order, with or without modifications, or refuse to make the order, and any person on whom notice has been served under subsection (3) shall be notified accordingly.
(6) Where a planning authority intends to amend or revoke an order made under this section, the planning authority shall give notice of its intention to amend or revoke the order, as the case may be.
(7) (a) A notice under subsection (6) (which shall include particulars of the proposed order) shall be—
(i) served on the owner and the occupier of the land affected by the order, and on any other person on whom a notice was served under subsection (3), and
(ii) published in one or more newspapers circulating in the functional area of the planning authority.
(b) A notice under subsection (6) shall be accompanied by a map indicating the tree, trees, group of trees or woodland to be affected by the amendment or revocation of the order.
(8) A notice under subsection (6) shall state that—
(a) the planning authority proposes to amend or revoke the order, and
(b) submissions of observations regarding the proposal may be made to the planning authority within a stated period of not less than 6 weeks, and that the submissions or observations will be taken into consideration by the planning authority.
(9) The planning authority, having considered the proposal and any submissions or observations made in respect of it, may by resolution, as it considers appropriate, revoke the order or amend the order, with or without modifications, or refuse to make the order, as the case may be, and any person on whom notice has been served under subsection (7) shall be notified accordingly.
(10) Any person who contravenes an order or, pending the decision of a planning authority, a proposed order under this section, shall be guilty of an offence.
(11) Without prejudice to any other exemption for which provision may be made by an order under this section, no such order shall apply to the cutting down, topping or lopping of trees which are dying or dead or have become dangerous, or the cutting down, topping or lopping of any trees in compliance with any obligation imposed by or under any enactment or so far as may be necessary for the prevention or abatement of a nuisance or hazard.
(12) Particulars of an order under this section shall be entered in the register
