There will be a special pensioner tax announced to fix this and will be paid direct to SBFU (The Swing Bridge Fixers Union) who will carry out the work over a 40 year period.
The work will be overseen by a guy closely involved in the HS2 build who estimated when this project was announced at the very beginning of April that the work could possibly cost more like 40 Million but if it does contingency plans are in place to raise the Pensioner levy.